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1

Laser Seeding Yields High-Power Coherent Terahertz Radiation  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Laser Seeding Yields High-Power Coherent Terahertz Radiation Laser Seeding Yields High-Power Coherent Terahertz Radiation Print Wednesday, 25 April 2007 00:00 Researchers at...

2

Laser Seeding Yields High-Power Coherent Terahertz Radiation  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

is generated in electron storage rings when femtosecond lasers are used to carve out ultrafast x-ray pulses by femtoslicing (see "Tailored Terahertz Pulses from a...

3

From high power terahertz quantum cascade lasers to terahertz light amplifiers  

E-Print Network [OSTI]

The terahertz (THz) frequency range (300 GHz to 10 THz, wavelength 30-1000 [mu]m), despite having many potential applications, is technologically relatively underdeveloped mainly because of the lack of suitable coherent ...

Kao, Tsung-Yu

2014-01-01T23:59:59.000Z

4

High power terahertz generation using 1550?nm plasmonic photomixers  

SciTech Connect (OSTI)

We present a 1550?nm plasmonic photomixer operating under pumping duty cycles below 10%, which offers significantly higher terahertz radiation power levels compared to previously demonstrated photomixers. The record-high terahertz radiation powers are enabled by enhancing the device quantum efficiency through use of plasmonic contact electrodes, and by mitigating thermal breakdown at high optical pump power levels through use of a low duty cycle optical pump. The repetition rate of the optical pump can be specifically selected at a given pump duty cycle to control the spectral linewidth of the generated terahertz radiation. At an average optical pump power of 150 mW with a pump modulation frequency of 1 MHz and pump duty cycle of 2%, we demonstrate up to 0.8 mW radiation power at 1 THz, within each continuous wave radiation cycle.

Berry, Christopher W. [Electrical Engineering and Computer Science Department, University of Michigan, Ann Arbor, Michigan 48109 (United States); Hashemi, Mohammad R.; Jarrahi, Mona [Electrical Engineering and Computer Science Department, University of Michigan, Ann Arbor, Michigan 48109 (United States); Electrical Engineering Department, University of California Los Angeles, Los Angeles, California 90095 (United States); Preu, Sascha [Department of Electrical Engineering and Information Technology, Technical University Darmstadt, D-64283 Darmstadt (Germany); Lu, Hong; Gossard, Arthur C. [Materials Department, University of California, Santa Barbara, California 93106 (United States)

2014-07-07T23:59:59.000Z

5

High-power terahertz optically pumped NH{sub 3} laser for plasma diagnostics  

SciTech Connect (OSTI)

The parameter of a terahertz (THz) laser intended for plasma diagnostics in electrodynamic accelerators and tokamaks with a strong magnetic field are discussed. Generation of THz radiation in an ammonia laser under the action of high-power pulsed optical pumping by the radiation of a 10P(32) CO{sub 2} laser is simulated numerically. The main characteristics of the output radiation, such as its spectrum, peak intensity, time dependence, and total energy, are calculated.

Mishchenko, V. A.; Petrushevich, Yu. V.; Sobolenko, D. N.; Starostin, A. N. [Troitsk Institute for Innovation and Fusion Research (Russian Federation)

2012-06-15T23:59:59.000Z

6

Laser Seeding Yields High-Power Coherent Terahertz Radiation  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: VegetationEquipment Surfaces and Interfaces Sample6, 2011 CERN 73-11LargeLaser EnablesLaserLaserLaser

7

Laser Seeding Yields High-Power Coherent Terahertz Radiation  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: VegetationEquipment Surfaces and Interfaces Sample6, 2011 CERN 73-11LargeLaser

8

Laser Seeding Yields High-Power Coherent Terahertz Radiation  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: VegetationEquipment Surfaces and Interfaces Sample6, 2011 CERN 73-11LargeLaserLaser Seeding Yields

9

Laser Seeding Yields High-Power Coherent Terahertz Radiation  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: VegetationEquipment Surfaces and Interfaces Sample6, 2011 CERN 73-11LargeLaserLaser Seeding YieldsLaser

10

Laser Seeding Yields High-Power Coherent Terahertz Radiation  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsruc DocumentationP-SeriesFlickrinformationPostdocs space CombinedValuesRevolutionizingLaserLaser

11

Laser Seeding Yields High-Power Coherent Terahertz Radiation  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsruc DocumentationP-SeriesFlickrinformationPostdocs space

12

Generation of high power pulsed terahertz radiation using a plasmonic photoconductive emitter array with logarithmic spiral antennas  

SciTech Connect (OSTI)

An array of 3?×?3 plasmonic photoconductive terahertz emitters with logarithmic spiral antennas is fabricated on a low temperature (LT) grown GaAs substrate and characterized in response to a 200 fs optical pump from a Ti:sapphire mode-locked laser at 800?nm wavelength. A microlens array is used to split and focus the optical pump beam onto the active area of each plasmonic photoconductive emitter element. Pulsed terahertz radiation with record high power levels up to 1.9 mW in the 0.1–2 THz frequency range is measured at an optical pump power of 320 mW. The record high power pulsed terahertz radiation is enabled by the use of plasmonic contact electrodes, enhancing the photoconductor quantum efficiencies, and by increasing the overall device active area, mitigating the carrier screening effect and thermal breakdown at high optical pump power levels.

Berry, Christopher W. [Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, Michigan 48109 (United States); Hashemi, Mohammad R.; Jarrahi, Mona [Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, Michigan 48109 (United States); Department of Electrical Engineering, University of California, Los Angeles, California 90095 (United States)

2014-02-24T23:59:59.000Z

13

Generation of high-power tunable terahertz-radiation by nonrelativistic beam-echo harmonic effect  

SciTech Connect (OSTI)

A new type of terahertz radiation source based on the nonrelativistic electron beam-wave interaction is proposed. Here, the beam echo harmonic effect is applied to a traveling wave tube like device. The scheme is configured as a combination of a frequency multiplier and amplifier with, for instance, W-band (millimeter wave) input signals and terahertz output power. A one-dimensional model of this device shows that a 10th order harmonic-wave can be generated while other harmonic waves are suppressed. The device only requires a readily available input source (W-band), and the output frequency can be tuned continuously over a wide band.

Gong Huarong; Xu Jin; Wei Yanyu; Gong Yubin [National Key Laboratory of Science and Technology on Vacuum Electronics, School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu, Sichuan 610054 (China); Travish, Gil [Department of Physics and Astronomy, University of California, Los Angeles, California 90095 (United States); Feng Jinjun [Vacuum Electronics National Laboratory, Vacuum Electronics research Institute, Beijing 100016 (China)

2013-01-15T23:59:59.000Z

14

Coherent and tunable terahertz radiation from graphene surface plasmon polaritons excited by an electron beam  

SciTech Connect (OSTI)

Although surface plasmon polaritons (SPPs) resonance in graphene can be tuned in the terahertz regime, transforming such SPPs into coherent terahertz radiation has not been achieved. Here, we propose a graphene-based coherent terahertz radiation source with greatly enhanced intensity. The radiation works at room temperature, it is tunable and can cover the whole terahertz regime. The radiation intensity generated with this method is 400 times stronger than that from SPPs at a conventional dielectric or semiconducting surface and is comparable to that from the most advanced photonics source such as a quantum cascade laser. The physical mechanism for this strong radiation is presented. The phase diagrams defining the parameters range for the occurrence of radiation is also shown.

Liu, Shenggang, E-mail: liusg@uestc.edu.cn; Hu, Min; Chen, Xiaoxing; Zhang, Ping; Gong, Sen; Zhao, Tao; Zhong, Renbin [Terahertz Research Centre, School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu, Sichuan 610054 (China); Cooperative Innovation Centre of Terahertz Science, Chengdu, Sichuan 610054 (China); Zhang, Chao [Terahertz Research Centre, School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu, Sichuan 610054 (China); Cooperative Innovation Centre of Terahertz Science, Chengdu, Sichuan 610054 (China); School of Physics and Institute for Superconducting and Electronic Materials, University of Wollongong, New South Wales 2522 (Australia)

2014-05-19T23:59:59.000Z

15

Generation of high power sub-terahertz radiation from a gyrotron with second harmonic oscillation  

SciTech Connect (OSTI)

New power records of second harmonic gyrotron oscillation have been demonstrated in the sub-THz band. The first step gyrotron of demountable type had succeeded in oscillation with power more than 50 kW at 350 GHz and nearly 40 kW at 390 GHz [T. Notake et al., Phys. Rev. Lett. 103, 225002 (2009)]. Then, the second step gyrotron of sealed-off type was manufactured. A cavity mode was carefully selected to avoid mode competition with a neighboring fundamental harmonic mode. Matching of the selected mode with the electron gun was also circumspectly considered. The second step gyrotron has attained higher power radiation than the first gyrotron. The maximum single mode power was 62 kW at 388 GHz. Then, the electron gun was modified for use of a different cavity mode with a higher coupling coefficient than that for the 62 kW mode. The new mode proved single mode oscillation power of 83 kW at about 389 GHz. These results are new second-harmonic-oscillation power records for sub-THz gyrotrons. The present study constitutes foundations of development of high power second harmonic sub-THz gyrotron for application to collective Thomson scattering measurement on fusion plasmas, especially on high-density plasmas such as those produced in LHD [N. Ohyabu et al., Phys. Rev. Lett. 97, 055002 (2006)]. This paper reports the design consideration to realize high power single mode gyrotron oscillation at second harmonic and the examination of oscillation characteristics of the gyrotron.

Saito, Teruo; Yamada, Naoki; Ikeuti, Shinji; Tatematsu, Yoshinori; Ikeda, Ryosuke; Ogawa, Isamu; Idehara, Toshitaka [Research Center for Development of Far-Infrared Region, University of Fukui, 3-9-1 Bunkyo, Fukui 910-8507 (Japan); Ogasawara, Shinya [Department of Energy Engineering and Science, Nagoya University, Nagoya 464-8463 (Japan); Manuilov, Vladimir N. [Nizhny Novgorod State University, Nizhny Novgorod 603600 (Russian Federation); Shimozuma, Takashi; Kubo, Shin; Nishiura, Masaki; Tanaka, Kenji; Kawahata, Kazuo [National Institute for Fusion Science, 322-6 Oroshi-cho, Toki 509-5292 (Japan)

2012-06-15T23:59:59.000Z

16

Tunable source of terahertz radiation using molecular modulation  

E-Print Network [OSTI]

Tunable source of terahertz radiation using molecular modulation D. D. Yavuz* and J. J. Weber a high power and widely tunable coher- ent source of THz radiation remains a very challenging task of terahertz (THz) radiation that is based on Raman down-shifting of an infrared laser beam using highly

Yavuz, Deniz

17

Intense terahertz pulses from SLAC electron beams using coherent transition radiation  

SciTech Connect (OSTI)

SLAC has two electron accelerators, the Linac Coherent Light Source (LCLS) and the Facility for Advanced Accelerator Experimental Tests (FACET), providing high-charge, high-peak-current, femtosecond electron bunches. These characteristics are ideal for generating intense broadband terahertz (THz) pulses via coherent transition radiation. For LCLS and FACET respectively, the THz pulse duration is typically 20 and 80 fs RMS and can be tuned via the electron bunch duration; emission spectra span 3-30 THz and 0.5 THz-5 THz; and the energy in a quasi-half-cycle THz pulse is 0.2 and 0.6 mJ. The peak electric field at a THz focus has reached 4.4 GV/m (0.44 V/A) at LCLS. This paper presents measurements of the terahertz pulses and preliminary observations of nonlinear materials response.

Wu Ziran; Fisher, Alan S.; Hogan, Mark; Loos, Henrik [Accelerator Directorate, SLAC National Accelerator Laboratory, Stanford University, 2575 Sand Hill Road, Menlo Park, California 94025 (United States); Goodfellow, John [Department of Materials Science and Engineering, Stanford University, Stanford, California 94305 (United States); Stanford Institute for Materials and Energy Science, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Fuchs, Matthias [Stanford Institute for Materials and Energy Science, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); PULSE Institute for Ultrafast Energy Science, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Daranciang, Dan [Department of Chemistry, Stanford University, Stanford, California 94305 (United States); Lindenberg, Aaron [Department of Materials Science and Engineering, Stanford University, Stanford, California 94305 (United States); Stanford Institute for Materials and Energy Science, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); PULSE Institute for Ultrafast Energy Science, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States)

2013-02-15T23:59:59.000Z

18

IKNO, a user facility for coherent terahertz and UV synchrotron radiation  

SciTech Connect (OSTI)

IKNO (Innovation and KNOwledge) is a proposal for a multi-user facility based on an electron storage ring optimized for the generation of coherent synchrotron radiation (CSR) in the terahertz frequency range, and of broadband incoherent synchrotron radiation (SR) ranging from the IR to the VUV. IKNO can be operated in an ultra-stable CSR mode with photon flux in the terahertz frequency region up to nine orders of magnitude higher than in existing 3rd generation light sources. Simultaneously to the CSR operation, broadband incoherent SR up to VUV frequencies is available at the beamline ports. The main characteristics of the IKNO storage and its performance in terms of CSR and incoherent SR are described in this paper. The proposed location for the infrastructure facility is in Sardinia, Italy.

Sannibale, Fernando; Marcelli, Augusto; Innocenzi, Plinio

2008-04-26T23:59:59.000Z

19

Single-cycle Terahertz Pulses with >0.2 V/A Field Amplitudes via Coherent Transition Radiation  

SciTech Connect (OSTI)

We demonstrate terahertz pulses with field amplitudes exceeding 0.2 V/{angstrom} generated by coherent transition radiation. Femtosecond, relativistic electron bunches generated at the Linac Coherent Light Source are passed through a beryllium foil, and the emitted radiation is characterized as a function of the bunch duration and charge. Broadband pulses centered at a frequency of 10 THz with energies of 140 {mu}J are measured. These far-below-bandgap pulses drive a nonlinear optical response in a silicon photodiode, with which we perform nonlinear autocorrelations that yield information regarding the terahertz temporal profile. Simulations of the spatiotemporal profile agree well with experimental results.

Daranciang, Dan; /Stanford U., Chem. Dept.; Goodfellow, John; /Stanford U. Materials Sci. Dept.; Fuchs, Matthias; /SIMES, Stanford /SLAC, PULSE; Wen, Haidan; /ANL, APS; Ghimire, Shambhu; /SLAC, PULSE; Reis, David A.; /SIMES, Sanford /SLAC, PULSE /Stanford U., Appl. Phys. Dept.; Loos, Henrik; Fisher, Alan S.; /SLAC, LCLS; Lindenberg, Aaron M.; /Stanford U. Materials Sci. Dept. /SIMES, Stanford /SLAC, PULSE

2012-02-15T23:59:59.000Z

20

Single-cycle terahertz pulses with >0.2 V/A field amplitudes via coherent transition radiation  

SciTech Connect (OSTI)

We demonstrate terahertz pulses with field amplitudes exceeding 0.2 V/A generated by coherent transition radiation. Femtosecond, relativistic electron bunches generated at the Linac Coherent Light Source are passed through a beryllium foil, and the emitted radiation is characterized as a function of the bunch duration and charge. Broadband pulses centered at a frequency of 10 THz with energies of 140 {mu}J are measured. These far-below-bandgap pulses drive a nonlinear optical response in a silicon photodiode, with which we perform nonlinear autocorrelations that yield information regarding the terahertz temporal profile. Simulations of the spatiotemporal profile agree well with experimental results.

Daranciang, Dan [Department of Chemistry, Stanford University, Stanford, California 94305 (United States); PULSE Institute for Ultrafast Energy Science, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Goodfellow, John [Department of Materials Science and Engineering, Stanford University, Stanford, California 94305 (United States); Stanford Institute for Materials and Energy Science, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Fuchs, Matthias; Ghimire, Shambhu [PULSE Institute for Ultrafast Energy Science, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Wen, Haidan [Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Reis, David A. [PULSE Institute for Ultrafast Energy Science, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Stanford Institute for Materials and Energy Science, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Department of Applied Physics, Stanford University, Stanford, California 94305 (United States); Loos, Henrik; Fisher, Alan S. [Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Lindenberg, Aaron M. [PULSE Institute for Ultrafast Energy Science, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Department of Materials Science and Engineering, Stanford University, Stanford, California 94305 (United States); Stanford Institute for Materials and Energy Science, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States)

2011-10-03T23:59:59.000Z

Note: This page contains sample records for the topic "high-power coherent terahertz" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

Coherence of resonant-tunneling transport in terahertz quantum-cascade lasers  

E-Print Network [OSTI]

We develop simple density-matrix models to describe the role of coherence in resonant-tunneling (RT) transport of quantum-cascade lasers (QCLs). Specifically, we investigate the effects of coherent coupling between the ...

Kumar, Sushil

22

Terahertz quantum cascade lasers  

E-Print Network [OSTI]

The development of the terahertz frequency range has long been impeded by the relative dearth of compact, coherent radiation sources of reasonable power. This thesis details the development of quantum cascade lasers (QCLs) ...

Williams, Benjamin S. (Benjamin Stanford), 1974-

2003-01-01T23:59:59.000Z

23

Room temperature broadband coherent terahertz emission induced by dynamical photon drag in graphene  

E-Print Network [OSTI]

Nonlinear couplings between photons and electrons in new materials give rise to a wealth of interesting nonlinear phenomena. This includes frequency mixing, optical rectification or nonlinear current generation, which are of particular interest for generating radiation in spectral regions that are difficult to access, such as the terahertz gap. Owing to its specific linear dispersion and high electron mobility at room temperature, graphene is particularly attractive for realizing strong nonlinear effects. However, since graphene is a centrosymmetric material, second-order nonlinearities a priori cancel, which imposes to rely on less attractive third-order nonlinearities. It was nevertheless recently demonstrated that dc-second-order nonlinear currents as well as ultrafast ac-currents can be generated in graphene under optical excitation. The asymmetry is introduced by the excitation at oblique incidence, resulting in the transfer of photon momentum to the electron system, known as the photon drag effect. Here...

Maysonnave, J; Wang, F; Maero, S; Berger, C; de Heer, W; Norris, T B; De Vaulchier, L A; Dhillon, S; Tignon, J; Ferreira, R; Mangeney, J

2015-01-01T23:59:59.000Z

24

Terahertz metamaterials  

DOE Patents [OSTI]

Terahertz metamaterials comprise a periodic array of resonator elements disposed on a dielectric substrate or thin membrane, wherein the resonator elements have a structure that provides a tunable magnetic permeability or a tunable electric permittivity for incident electromagnetic radiation at a frequency greater than about 100 GHz and the periodic array has a lattice constant that is smaller than the wavelength of the incident electromagnetic radiation. Microfabricated metamaterials exhibit lower losses and can be assembled into three-dimensional structures that enable full coupling of incident electromagnetic terahertz radiation in two or three orthogonal directions. Furthermore, polarization sensitive and insensitive metamaterials at terahertz frequencies can enable new devices and applications.

Peralta, Xomalin Guaiuli; Brener, Igal; O'Hara, John; Azad, Abul; Smirnova, Evgenya; Williams, John D.; Averitt, Richard D.

2014-08-12T23:59:59.000Z

25

High Power Cryogenic Targets  

SciTech Connect (OSTI)

The development of high power cryogenic targets for use in parity violating electron scattering has been a crucial ingredient in the success of those experiments. As we chase the precision frontier, the demands and requirements for these targets have grown accordingly. We discuss the state of the art, and describe recent developments and strategies in the design of the next generation of these targets.

Gregory Smith

2011-08-01T23:59:59.000Z

26

High power microwave generator  

DOE Patents [OSTI]

A microwave generator efficiently converts the energy of an intense relativistic electron beam (REB) into a high-power microwave emission using the Smith-Purcell effect which is related to Cerenkov radiation. Feedback for efficient beam bunching and high gain is obtained by placing a cylindrical Smith-Purcell transmission grating on the axis of a toroidal resonator. High efficiency results from the use of a thin cold annular highly-magnetized REB that is closely coupled to the resonant structure.

Ekdahl, C.A.

1983-12-29T23:59:59.000Z

27

Numerical study on a 0.4 THz second harmonic gyrotron with high power  

SciTech Connect (OSTI)

Terahertz and sub-terahertz science and technology are promising topics today. However, it is difficult to obtain high power source of terahertz wave. In this paper, the mode competition and beam-wave interaction in a gradually tapered cavity are studied to achieve high efficiency of a 0.4THz second harmonic gyrotron in practice. In order to attain high power and stable radiation, the TE{sub 32,5} mode is selected as the operating mode of the desired gyrotron to realize single mode oscillation. The issues of studying on the high-order mode gyrotrons are solved effectively by transforming the generalized telegraphist's equations. The efficiency and output power of the gyrotron under different conditions have been calculated by the code, which is based on the transformed equations. Consequently, the results show that single mode second harmonic radiation with power of over 150 kW at frequency of 0.4 THz could be achieved.

Chaojun, Lei [Terahertz Science and Technology Research Center, University of Electronics Science and Technology of China, Chengdu 610054 (China) [Terahertz Science and Technology Research Center, University of Electronics Science and Technology of China, Chengdu 610054 (China); The Chinese People's Armed Police Force Academy, Langfang 065000 (China); Sheng, Yu; Hongfu, Li; Yinghui, Liu; Xinjian, Niu; Qixiang, Zhao [Terahertz Science and Technology Research Center, University of Electronics Science and Technology of China, Chengdu 610054 (China)] [Terahertz Science and Technology Research Center, University of Electronics Science and Technology of China, Chengdu 610054 (China)

2013-07-15T23:59:59.000Z

28

High power connection system  

DOE Patents [OSTI]

A high power connection system adapted for automotive environments which provides environmental and EMI shielding includes a female connector, a male connector, and a panel mount. The female connector includes a female connector base and a snap fitted female connector cover. The male connector includes a male connector base and a snap fitted male connector cover. The female connector base has at least one female power terminal cavity for seatably receiving a respective female power terminal. The male connector base has at least one male power terminal cavity for seatably receiving a respective male power terminal. The female connector is covered by a cover seal and a conductive shroud. A pair of lock arms protrude outward from the front end of the male connector base, pass through the panel mount and interface with a lever of a lever rotatably connected to the shroud to thereby mechanically assist mating of the male and female connectors. Safety terminals in the male and female connectors provide a last-to-connect-first-to-break connection with an HVIL circuit.

Schaefer, Christopher E. (Warren, OH); Beer, Robert C. (Noblesville, IN); McCall, Mark D. (Youngstown, OH)

2000-01-01T23:59:59.000Z

29

Resonance laser-plasma excitation of coherent terahertz phonons in the bulk of fluorine-bearing crystals under high-intensity femtosecond laser irradiation  

SciTech Connect (OSTI)

The dynamics of coherent phonons in fluorine-containing crystals was investigated by pump-probe technique in the plasma production regime. Several phonon modes, whose frequencies are overtones of the 0.38-THz fundamental frequency, were simultaneously observed in a lithium fluoride crystal. Phonons with frequencies of 1 and 0.1 THz were discovered in a calcium fluoride crystal and coherent phonons with frequencies of 1 THz and 67 GHz were observed in a barium fluoride crystal. Furthermore, in the latter case the amplitudes of phonon mode oscillations were found to significantly increase 15 ps after laser irradiation. (interaction of laser radiation with matter)

Potemkin, F V; Mareev, E I [International Laser Center, M. V. Lomonosov Moscow State University, Moscow (Russian Federation); Khodakovskii, N G [A M Prokhorov General Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation); Mikheev, P M

2013-08-31T23:59:59.000Z

30

Terahertz radiation by optical rectification in a hydrogen-bonded organic molecular ferroelectric crystal, 2-phenylmalondialdehyde  

E-Print Network [OSTI]

Terahertz radiation by optical rectification has been observed at room temperature in a hydrogen-bonded organic molecular ferroelectric crystal, 2-phenyl malondialdehyde (PhMDA). The radiated electromagnetic wave consisted of a single-cycle terahertz pulse with a temporal width of $\\sim$ 0.5 ps. The terahertz radiation amplitude divided by the sample thickness in PhMDA was nearly equivalent to that in a typical terahertz wave emitter ZnTe. This is attributable to a long coherence length in the range of 130 $\\sim$ 800 $\\mu$m for the terahertz radiation from PhMDA. We also discussed the possibility of PhMDA as a terahertz wave emitter in terms of the phase-matching condition.

Guan, W; Sotome, M; Kinoshita, Y; Takeda, R; Inoue, A; Horiuchi, S; Okamoto, H

2014-01-01T23:59:59.000Z

31

Observation of Coherently-Enhanced Tunable Narrow-Band Terahertz Transition Radiation from a Relativistic Sub-Picosecond Electron Bunch Train  

DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

We experimentally demonstrate the production of narrow-band (?f/f ~ =20% at f ~ = 0.5 THz) THz transition radiation with tunable frequency over [0.37, 0.86] THz. The radiation is produced as a train of sub-picosecond relativistic electron bunches transits at the vacuum-aluminum interface of an aluminum converter screen. We also show a possible application of modulated beams to extend the dynamical range of a popular bunch length diagnostic technique based on the spectral analysis of coherent radiation.

Piot, P [Northern Illinois U.; Fermilab; Sun, Y E [Fermilab; Maxwell, T J [Fermilab; Northern Illinois U.; Ruan, J.; Lumpkin, A H [Fermilab; Rihaoui, M M [Northern Illinois U.; Thurman-Keup, R [Fermilab

2011-06-27T23:59:59.000Z

32

Integrated heterodyne terahertz transceiver  

DOE Patents [OSTI]

A heterodyne terahertz transceiver comprises a quantum cascade laser that is integrated on-chip with a Schottky diode mixer. A terahertz signal can be received by an antenna connected to the mixer, an end facet or sidewall of the laser, or through a separate active section that can amplify the incident signal. The quantum cascade laser couples terahertz local oscillator power to the Schottky diode to mix with the received terahertz signal to provide an intermediate frequency output signal. The fully integrated transceiver optimizes power efficiency, sensitivity, compactness, and reliability. The transceiver can be used in compact, fieldable systems covering a wide variety of deployable applications not possible with existing technology.

Wanke, Michael C. (Albuquerque, NM); Lee, Mark (Albuquerque, NM); Nordquist, Christopher D. (Albuquerque, NM); Cich, Michael J. (Albuquerque, NM)

2012-09-25T23:59:59.000Z

33

Integrated heterodyne terahertz transceiver  

DOE Patents [OSTI]

A heterodyne terahertz transceiver comprises a quantum cascade laser that is integrated on-chip with a Schottky diode mixer. An antenna connected to the Schottky diode receives a terahertz signal. The quantum cascade laser couples terahertz local oscillator power to the Schottky diode to mix with the received terahertz signal to provide an intermediate frequency output signal. The fully integrated transceiver optimizes power efficiency, sensitivity, compactness, and reliability. The transceiver can be used in compact, fieldable systems covering a wide variety of deployable applications not possible with existing technology.

Lee, Mark (Albuquerque, NM); Wanke, Michael C. (Albuquerque, NM)

2009-06-23T23:59:59.000Z

34

Metamaterials for terahertz polarimetric devices  

SciTech Connect (OSTI)

We present experimental and numerical investigations of planar terahertz metamaterial structures designed to interact with the state of polarization. The dependence of metamaterial resonances on polarization results in unique amplitude and phase characteristics of the terahertz transmission, providing the basis for polarimetric terahertz devices. We highlight some potential applications for polarimetric devices and present simulations of a terahertz quarter-wave plate and a polarizing terahertz beam splitter. Although this work was performed at terahertz frequencies, it may find applications in other frequency ranges as well.

O'hara, John F [Los Alamos National Laboratory; Taylor, Antoinette J [Los Alamos National Laboratory; Smirnova, Evgenya [Los Alamos National Laboratory; Azad, Abul [Los Alamos National Laboratory

2008-01-01T23:59:59.000Z

35

Active terahertz metamaterials  

SciTech Connect (OSTI)

We demonstrate planar terahertz metamaterial devices enabling actively controllable transmission amplitude, phase, or frequency at room temperature via carrier depletion or photoexcitation in the semiconductor substrate or in semiconductor materials incorporated into the metamaterial structure.

Chen, Hou-tong [Los Alamos National Laboratory

2009-01-01T23:59:59.000Z

36

Broadband terahertz photonics  

E-Print Network [OSTI]

In recent years, quantum cascade lasers have emerged as mature semiconductor sources of light in the terahertz range, the frequency range spanning 1 to 10 THz. Though technological development has pushed their operating ...

Burghoff, David Patrick

2014-01-01T23:59:59.000Z

37

Coherent beam combiner for a high power laser  

DOE Patents [OSTI]

A phase conjugate laser mirror employing Brillouin-enhanced four wave mixing allows multiple independent laser apertures to be phase locked producing an array of diffraction-limited beams with no piston phase errors. The beam combiner has application in laser and optical systems requiring high average power, high pulse energy, and low beam divergence. A broad range of applications exist in laser systems for industrial processing, especially in the field of metal surface treatment and laser shot peening.

Dane, C. Brent (Livermore, CA); Hackel, Lloyd A. (Livermore, CA)

2002-01-01T23:59:59.000Z

38

High-Power Rf Load  

DOE Patents [OSTI]

A compact high-power RF load comprises a series of very low Q resonators, or chokes [16], in a circular waveguide [10]. The sequence of chokes absorb the RF power gradually in a short distance while keeping the bandwidth relatively wide. A polarizer [12] at the input end of the load is provided to convert incoming TE.sub.10 mode signals to circularly polarized TE.sub.11 mode signals. Because the load operates in the circularly polarized mode, the energy is uniformly and efficiently absorbed and the load is more compact than a rectangular load. Using these techniques, a load having a bandwidth of 500 MHz can be produced with an average power dissipation level of 1.5 kW at X-band, and a peak power dissipation of 100 MW. The load can be made from common lossy materials, such as stainless steel, and is less than 15 cm in length. These techniques can also produce loads for use as an alternative to ordinary waveguide loads in small and medium RF accelerators, in radar systems, and in other microwave applications. The design is easily scalable to other RF frequencies and adaptable to the use of other lossy materials.

Tantawi, Sami G. (San Mateo, CA); Vlieks, Arnold E. (Livermore, CA)

1998-09-01T23:59:59.000Z

39

Abuse Testing of High Power Batteries  

Broader source: Energy.gov (indexed) [DOE]

not contain any proprietary or confidential information Abuse Testing of High Power Batteries Sandia National Laboratories Overview * Start Date: Oct. 2007 * End date: Sept. 2014...

40

Abuse Testing of High Power Batteries  

Broader source: Energy.gov (indexed) [DOE]

Sandia National Laboratories Abuse Testing of High Power Batteries Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United...

Note: This page contains sample records for the topic "high-power coherent terahertz" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

Terahertz radiation mixer  

DOE Patents [OSTI]

A terahertz radiation mixer comprises a heterodyned field-effect transistor (FET) having a high electron mobility heterostructure that provides a gatable two-dimensional electron gas in the channel region of the FET. The mixer can operate in either a broadband pinch-off mode or a narrowband resonant plasmon mode by changing a grating gate bias of the FET. The mixer can beat an RF signal frequency against a local oscillator frequency to generate an intermediate frequency difference signal in the microwave region. The mixer can have a low local oscillator power requirement and a large intermediate frequency bandwidth. The terahertz radiation mixer is particularly useful for terahertz applications requiring high resolution.

Wanke, Michael C. (Albuquerque, NM); Allen, S. James (Santa Barbara, CA); Lee, Mark (Albuquerque, NM)

2008-05-20T23:59:59.000Z

42

Advanced, High Power, Next Scale, Wave Energy Conversion Device...  

Broader source: Energy.gov (indexed) [DOE]

Advanced, High Power, Next Scale, Wave Energy Conversion Device Advanced, High Power, Next Scale, Wave Energy Conversion Device Advanced, High Power, Next Scale, Wave Energy...

43

Tunable terahertz radiation source  

SciTech Connect (OSTI)

Terahertz radiation source and method of producing terahertz radiation, said source comprising a junction stack, said junction stack comprising a crystalline material comprising a plurality of self-synchronized intrinsic Josephson junctions; an electrically conductive material in contact with two opposing sides of said crystalline material; and a substrate layer disposed upon at least a portion of both the crystalline material and the electrically-conductive material, wherein the crystalline material has a c-axis which is parallel to the substrate layer, and wherein the source emits at least 1 mW of power.

Boulaevskii, Lev; Feldmann, David M; Jia, Quanxi; Koshelev, Alexei; Moody, Nathan A

2014-01-21T23:59:59.000Z

44

High power laser perforating tools and systems  

DOE Patents [OSTI]

ystems devices and methods for the transmission of 1 kW or more of laser energy deep into the earth and for the suppression of associated nonlinear phenomena. Systems, devices and methods for the laser perforation of a borehole in the earth. These systems can deliver high power laser energy down a deep borehole, while maintaining the high power to perforate such boreholes.

Zediker, Mark S; Rinzler, Charles C; Faircloth, Brian O; Koblick, Yeshaya; Moxley, Joel F

2014-04-22T23:59:59.000Z

45

High power rechargeable batteries Paul V. Braun  

E-Print Network [OSTI]

High power rechargeable batteries Paul V. Braun , Jiung Cho, James H. Pikul, William P. King storage Secondary batteries High energy density High power density Lithium ion battery 3D battery electrodes a b s t r a c t Energy and power density are the key figures of merit for most electrochemical

Braun, Paul

46

An ultrafast carbon nanotube terahertz polarisation modulator  

SciTech Connect (OSTI)

We demonstrate ultrafast modulation of terahertz radiation by unaligned optically pumped single-walled carbon nanotubes. Photoexcitation by an ultrafast optical pump pulse induces transient terahertz absorption in nanowires aligned parallel to the optical pump. By controlling the polarisation of the optical pump, we show that terahertz polarisation and modulation can be tuned, allowing sub-picosecond modulation of terahertz radiation. Such speeds suggest potential for semiconductor nanowire devices in terahertz communication technologies.

Docherty, Callum J.; Stranks, Samuel D.; Habisreutinger, Severin N.; Joyce, Hannah J.; Herz, Laura M.; Nicholas, Robin J.; Johnston, Michael B., E-mail: m.johnston@physics.ox.ac.uk [Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU (United Kingdom)

2014-05-28T23:59:59.000Z

47

Cavity enhanced terahertz modulation  

SciTech Connect (OSTI)

We present a versatile concept for all optical terahertz (THz) amplitude modulators based on a Fabry-Pérot semiconductor cavity design. Employing the high reflectivity of two parallel meta-surfaces allows for trapping selected THz photons within the cavity and thus only a weak optical modulation of the semiconductor absorbance is required to significantly damp the field within the cavity. The optical switching yields to modulation depths of more than 90% with insertion efficiencies of 80%.

Born, N., E-mail: norman.born@physik.uni-marburg.de [College of Optical Sciences, University of Arizona, 1630 E University Boulevard, Tucson, Arizona 85721 (United States); Faculty of Physics and Material Sciences Center, Philipps-Universität Marburg, Renthof 5, 35032 Marburg (Germany); Scheller, M.; Moloney, J. V. [College of Optical Sciences, University of Arizona, 1630 E University Boulevard, Tucson, Arizona 85721 (United States)] [College of Optical Sciences, University of Arizona, 1630 E University Boulevard, Tucson, Arizona 85721 (United States); Koch, M. [Faculty of Physics and Material Sciences Center, Philipps-Universität Marburg, Renthof 5, 35032 Marburg (Germany)] [Faculty of Physics and Material Sciences Center, Philipps-Universität Marburg, Renthof 5, 35032 Marburg (Germany)

2014-03-10T23:59:59.000Z

48

Plasma Switch for High-Power Active Pulse Compressor  

SciTech Connect (OSTI)

Results are presented from experiments carried out at the Naval Research Laboratory X-band magnicon facility on a two-channel X-band active RF pulse compressor that employed plasma switches. Experimental evidence is shown to validate the basic goals of the project, which include: simultaneous firing of plasma switches in both channels of the RF circuit, operation of quasi-optical 3-dB hybrid directional coupler coherent superposition of RF compressed pulses from both channels, and operation of the X-band magnicon directly in the RF pulse compressor. For incident 1.2 ?s pulses in the range 0.63 ? 1.35 MW, compressed pulses of peak powers 5.7 ? 11.3 MW were obtained, corresponding to peak power gain ratios of 8.3 ? 9.3. Insufficient bakeout and conditioning of the high-power RF circuit prevented experiments from being conducted at higher RF input power levels.

Hirshfield, Jay L. [Omega-P, Inc.] [Omega-P, Inc.

2013-11-04T23:59:59.000Z

49

High Power Co-Axial Coupler  

SciTech Connect (OSTI)

A very high power Coax RF Coupler (MW-Level) is very desirable for a number of accelerator and commercial applications. For example, the development of such a coupler operating at 1.5 GHz may permit the construction of a higher-luminosity version of the Electron-Ion Collider (EIC) being planned at JLab. Muons, Inc. is currently funded by a DOE STTR grant to develop a 1.5-GHz high-power doublewindowcoax coupler with JLab (about 150 kW). Excellent progress has been made on this R&D project, so we propose an extension of this development to build a very high power coax coupler (MW level peak power and a max duty factor of about 4%). The dimensions of the current coax coupler will be scaled up to provide higher power capability.

Neubauer, M. [Muons, Inc.; Dudas, A. [Muons, Inc.; Rimmer, Robert A. [JLAB; Guo, Jiquan [JLAB; Williams, R. Scott [JLAB

2013-12-01T23:59:59.000Z

50

Plasma physics and related challenges of millimeter-wave-to-terahertz and high power microwave generationa...  

E-Print Network [OSTI]

, the challenges have yet to be completely met for applications including noninvasive sensing of concealed weapons frequency electromagnetic radiation,1 confirming the theoretical prediction by Maxwell that visible light of the first applications for powerful radio waves, i.e., radar.4 Immediately recognizing the implications

Smith, James E.

51

Modeling Combustion Control for High Power Diesel Mode Switching...  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

Combustion Control for High Power Diesel Mode Switching Modeling Combustion Control for High Power Diesel Mode Switching Poster presentation given at the 16th Directions in...

52

High power density supercapacitors using locally aligned carbon nanotube electrodes  

E-Print Network [OSTI]

High power density supercapacitors using locally alignedof high power density supercapacitors and other similarcells [6], and for supercapacitors [7–18]. As unique energy

Du, C S; Yeh, J; Pan, Ning

2005-01-01T23:59:59.000Z

53

Modeling Combustion Control for High Power Diesel Mode Switching  

Broader source: Energy.gov (indexed) [DOE]

and Emissions Research Conference 2010 Modeling Combustion Control for High Power Diesel Mode Switching P-20 Motivation * High power LTC-diesel mode operation * Transient...

54

USABC Energy Storage Testing - High Power and PHEV Development...  

Energy Savers [EERE]

Energy Storage Testing - High Power and PHEV Development USABC Energy Storage Testing - High Power and PHEV Development Presentation from the U.S. DOE Office of Vehicle...

55

Energy Storage Testing and Analysis High Power and High Energy...  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

Testing and Analysis High Power and High Energy Development Energy Storage Testing and Analysis High Power and High Energy Development 2009 DOE Hydrogen Program and Vehicle...

56

High Power Proton Accelerators: Capabilities and  

E-Print Network [OSTI]

;Charge neutral deeply penetrating Li motion in fuel cells Help build electric cars Nuclear scattering-Battelle for the U.S. Department of Energy "Rough" Outline · Why high power proton accelerators? · Brief introduction energy to probe for smaller and smaller particles. The SNS is part of class of accelerators called

Tennessee, University of

57

Active terahertz metamaterials  

SciTech Connect (OSTI)

In this paper we present an overview of research in our group in terahertz (THz) metamaterials and their applications. We have developed a series of planar metamaterials operating at THz frequencies, all of which exhibit a strong resonant response. By incorporating natural materials, e.g. semiconductors, as the substrates or as critical regions of metamaterial elements, we are able to effectively control the metamaterial resonance by the application of external stimuli, e.g., photoexcitation and electrical bias. Such actively controllable metamaterials provide novel functionalities for solid-state device applications with unprecedented performance, such as THz spectroscopy, imaging, and many others.

Chen, Hou-tong [Los Alamos National Laboratory; O' Hara, John F [Los Alamos National Laboratory; Taylor, Antoinette J [Los Alamos National Laboratory

2009-01-01T23:59:59.000Z

58

High Power UV LED Industrial Curing Systems  

SciTech Connect (OSTI)

UV curing is a green technology that is largely underutilized because UV radiation sources like Hg Lamps are unreliable and difficult to use. High Power UV LEDs are now efficient enough to replace Hg Lamps, and offer significantly improved performance relative to Hg Lamps. In this study, a modular, scalable high power UV LED curing system was designed and tested, performing well in industrial coating evaluations. In order to achieve mechanical form factors similar to commercial Hg Lamp systems, a new patent pending design was employed enabling high irradiance at long working distances. While high power UV LEDs are currently only available at longer UVA wavelengths, rapid progress on UVC LEDs and the development of new formulations designed specifically for use with UV LED sources will converge to drive more rapid adoption of UV curing technology. An assessment of the environmental impact of replacing Hg Lamp systems with UV LED systems was performed. Since UV curing is used in only a small portion of the industrial printing, painting and coating markets, the ease of use of UV LED systems should increase the use of UV curing technology. Even a small penetration of the significant number of industrial applications still using oven curing and drying will lead to significant reductions in energy consumption and reductions in the emission of green house gases and solvent emissions.

Karlicek, Robert, F., Jr; Sargent, Robert

2012-05-14T23:59:59.000Z

59

Water Cooling of High Power Light Emitting Diode Henrik Srensen  

E-Print Network [OSTI]

Water Cooling of High Power Light Emitting Diode Henrik Sørensen Department of Energy Technology and product lifetime. The high power Light Emitting Diodes (LED) belongs to the group of electronics

Berning, Torsten

60

High Power, Linear CMOS Power Amplifier for WLAN Applications /  

E-Print Network [OSTI]

components in silicon, achieving a high power enhancement ratio from a single stage LC matching network or single transformer

Afsahi, Ali

2013-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "high-power coherent terahertz" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

The generation of high field terahertz radiation and its application in terahertz nonlinear spectroscopy  

E-Print Network [OSTI]

In this thesis research, I implemented a terahertz generation scheme that enables high-field near-single-cycle terahertz (THz) pulse generation via optical rectification in a LiNbO3 (LN) crystal. I also developed a method ...

Yeh, Ka-Lo

2009-01-01T23:59:59.000Z

62

High power density solid oxide fuel cells  

DOE Patents [OSTI]

A method for producing ultra-high power density solid oxide fuel cells (SOFCs). The method involves the formation of a multilayer structure cells wherein a buffer layer of doped-ceria is deposited intermediate a zirconia electrolyte and a cobalt iron based electrode using a colloidal spray deposition (CSD) technique. For example, a cobalt iron based cathode composed of (La,Sr)(Co,Fe)O (LSCF) may be deposited on a zirconia electrolyte via a buffer layer of doped-ceria deposited by the CSD technique. The thus formed SOFC have a power density of 1400 mW/cm.sup.2 at 600.degree. C. and 900 mW/cm.sup.2 at 700.degree. C. which constitutes a 2-3 times increased in power density over conventionally produced SOFCs.

Pham, Ai Quoc; Glass, Robert S.

2004-10-12T23:59:59.000Z

63

Terahertz detection and carbon nanotubes  

ScienceCinema (OSTI)

Researchers at Sandia National Laboratories, along with collaborators from Rice University and the Tokyo Institute of Technology, are developing new terahertz detectors based on carbon nanotubes that could lead to significant improvements in medical imaging, airport passenger screening, food inspection and other applications.

Leonard, Francois

2014-06-13T23:59:59.000Z

64

Terahertz detection and carbon nanotubes  

SciTech Connect (OSTI)

Researchers at Sandia National Laboratories, along with collaborators from Rice University and the Tokyo Institute of Technology, are developing new terahertz detectors based on carbon nanotubes that could lead to significant improvements in medical imaging, airport passenger screening, food inspection and other applications.

Leonard, Francois

2014-06-11T23:59:59.000Z

65

Terahertz antireflection coatings using metamaterials  

SciTech Connect (OSTI)

We demonstrate terahertz metamaterial antireflection coatings (ARCs) that significantly reduce the reflection and enhance the transmission at an interface of dielectric media. They are able to operate over a wide range of incidence angles for both TM and TE polarizations. Experiments and finite-element simulations will be presented and discussed.

Chen, Hou-tong [Los Alamos National Laboratory; Zhou, Jiangfeng [Los Alamos National Laboratory; O' Hara, John F [Los Alamos National Laboratory; Azad, Abul K [Los Alamos National Laboratory; Chen, Frank [Los Alamos National Laboratory; Taylor, Antoinette J [Los Alamos National Laboratory

2010-01-01T23:59:59.000Z

66

Electrically tunable terahertz quantum cascade lasers  

E-Print Network [OSTI]

In this thesis, microelectromechanical systems (MEMS) assisted electrically tunable terahertz quantum cascade lasers (THz QCLs) are designed and demonstrated. Two MEMS tuner devices are proposed to achieve electrically ...

Han, Ningren

2013-01-01T23:59:59.000Z

67

High power, high beam quality regenerative amplifier  

DOE Patents [OSTI]

A regenerative laser amplifier system generates high peak power and high energy per pulse output beams enabling generation of X-rays used in X-ray lithography for manufacturing integrated circuits. The laser amplifier includes a ring shaped optical path with a limited number of components including a polarizer, a passive 90 degree phase rotator, a plurality of mirrors, a relay telescope, and a gain medium, the components being placed close to the image plane of the relay telescope to reduce diffraction or phase perturbations in order to limit high peak intensity spiking. In the ring, the beam makes two passes through the gain medium for each transit of the optical path to increase the amplifier gain to loss ratio. A beam input into the ring makes two passes around the ring, is diverted into an SBS phase conjugator and proceeds out of the SBS phase conjugator back through the ring in an equal but opposite direction for two passes, further reducing phase perturbations. A master oscillator inputs the beam through an isolation cell (Faraday or Pockels) which transmits the beam into the ring without polarization rotation. The isolation cell rotates polarization only in beams proceeding out of the ring to direct the beams out of the amplifier. The diffraction limited quality of the input beam is preserved in the amplifier so that a high power output beam having nearly the same diffraction limited quality is produced.

Hackel, L.A.; Dane, C.B.

1993-08-24T23:59:59.000Z

68

High power, high beam quality regenerative amplifier  

DOE Patents [OSTI]

A regenerative laser amplifier system generates high peak power and high energy per pulse output beams enabling generation of X-rays used in X-ray lithography for manufacturing integrated circuits. The laser amplifier includes a ring shaped optical path with a limited number of components including a polarizer, a passive 90 degree phase rotator, a plurality of mirrors, a relay telescope, and a gain medium, the components being placed close to the image plane of the relay telescope to reduce diffraction or phase perturbations in order to limit high peak intensity spiking. In the ring, the beam makes two passes through the gain medium for each transit of the optical path to increase the amplifier gain to loss ratio. A beam input into the ring makes two passes around the ring, is diverted into an SBS phase conjugator and proceeds out of the SBS phase conjugator back through the ring in an equal but opposite direction for two passes, further reducing phase perturbations. A master oscillator inputs the beam through an isolation cell (Faraday or Pockels) which transmits the beam into the ring without polarization rotation. The isolation cell rotates polarization only in beams proceeding out of the ring to direct the beams out of the amplifier. The diffraction limited quality of the input beam is preserved in the amplifier so that a high power output beam having nearly the same diffraction limited quality is produced.

Hackel, Lloyd A. (Livermore, CA); Dane, Clifford B. (Livermore, CA)

1993-01-01T23:59:59.000Z

69

High power THz sources for nonlinear imaging  

SciTech Connect (OSTI)

Many biological and chemical compounds have unique absorption features in the THz (0.1 - 10 THz) region, making the use of THz waves attractive for imaging in defense, security, biomedical imaging, and monitoring of industrial processes. Unlike optical radiation, THz frequencies can pass through many substances such as paper, clothing, ceramic, etc. with little attenuation. The use of currently available THz systems is limited by lack of highpower, sources as well as sensitive detectors and detector arrays operating at room temperature. Here we present a novel, high power THz source based on intracavity downconverison of optical pulses. The source delivers 6 ps pulses at 1.5 THz, with an average power of >300 ?W and peak powers >450 mW. We propose an imaging method based on frequency upconverison that is ideally suited to use the narrow bandwidth and high peak powers produced by the source. By upconverting the THz image to the infrared, commercially available detectors can be used for real time imaging.

Tekavec, Patrick F.; Kozlov, Vladimir G. [Microtech Instruments, 858 West Park Street, Eugene, OR 97401 (United States)

2014-02-18T23:59:59.000Z

70

Novel Manufacturing Technologies for High Power Induction and...  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

High Power Induction and Permanent Magnet Electric Motors 2012 DOE Hydrogen and Fuel Cells Program and Vehicle Technologies Program Annual Merit Review and Peer Evaluation...

71

Double negative-metamaterial based Terahertz radiation excited by a sheet beam bunch  

SciTech Connect (OSTI)

We describe a new method to generate enhanced terahertz (THz) surface wave (SW) via its coupling with reversed Cherenkov radiation (RCR), excited by a sheet beam bunch which travels in a vacuum above an isotropic double negative metamaterial (DNM). The physical mechanism for the enhancement is that the DNM can support a RCR which can resonantly interact with a sheet electron beam bunch, resulting in an enhanced SW due to its coupling with the enhanced RCR. Numerical results show strong enhancement effect for the SW and RCR in the THz band. This enhanced THz radiation has potential applications to high-power THz radiation sources and Cherenkov detectors which require large signals.

Duan, Zhaoyun [Institute of High Energy Electronics, School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu 610054 (China) [Institute of High Energy Electronics, School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu 610054 (China); Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Guo, Chen [Southwest China Institute of Electronic Technology, Chengdu 610036 (China)] [Southwest China Institute of Electronic Technology, Chengdu 610036 (China); Guo, Xin [Institute of High Energy Electronics, School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu 610054 (China)] [Institute of High Energy Electronics, School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu 610054 (China); Chen, Min [Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)] [Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

2013-09-15T23:59:59.000Z

72

Terahertz generation by two cross focused laser beams in collisional plasmas  

SciTech Connect (OSTI)

The role of two cross-focused spatial-Gaussian laser beams has been studied for the high power and efficient terahertz (THz) radiation generation in the collisional plasma. The nonlinear current at THz frequency arises on account of temperature dependent collision frequency of electrons with ions in the plasma and the presence of a static electric field (applied externally in the plasma) and density ripple. Optimisation of laser-plasma parameters gives the radiated THz power of the order of 0.23??MW.

Sharma, R. P., E-mail: rpsharma@ces.iitd.ernet.in; Singh, Ram Kishor, E-mail: ram007kishor@gmail.com [Centre for Energy Studies, Indian Institute of Technology Delhi, New Delhi 110016 (India)

2014-07-15T23:59:59.000Z

73

Graphene plasmonics for tunable terahertz metamaterials  

E-Print Network [OSTI]

Graphene plasmonics for tunable terahertz metamaterials Long Ju1 , Baisong Geng1,6 , Jason Horng1 metamaterials1­3 . Plasmons of two-dimensional massless electrons, as present in graphene, show unusual graphene micro- ribbonarrays.Wedemonstratethatgrapheneplasmonresonances can be tuned over a broad terahertz

Wang, Feng

74

Coherent Control of Ballistic Photocurrents in Multilayer Epitaxial Graphene Using Quantum Interference  

E-Print Network [OSTI]

Coherent Control of Ballistic Photocurrents in Multilayer Epitaxial Graphene Using Quantum report generation of ballistic electric currents in unbiased epitaxial graphene at 300 K via quantum. The transient currents are detected via the emitted terahertz radiation. Because of graphene's special structure

Recanati, Catherine

75

OPERATIONAL ASPECTS OF HIGH POWER ENERGY RECOVERY LINACS  

SciTech Connect (OSTI)

We have been operating a high-power energy-recovery linac (ERL) at Jefferson Lab for several years. In the process we have learned quite a bit about both technical and physics limitations in high power ERLs. Several groups are now considering new ERLs that greatly increase either the energy, the current or both. We will present some of our findings on what to consider when designing, building, and operating a high power ERL. Our remarks for this paper are limited to lattice design and setup, magnets, vacuum chamber design, diagnostics, and beam stability.

Stephen Benson; David Douglas; Pavel Evtushenko; Kevin Jordan; George Neil; Paul Powers

2006-08-21T23:59:59.000Z

76

assisted high power: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

V. Braun , Jiung Cho, James H. Pikul, William P. King storage Secondary batteries High energy density High power density Lithium ion battery 3D battery electrodes a b s t r a c t...

77

Innovative fuel designs for high power density pressurized water reactor  

E-Print Network [OSTI]

One of the ways to lower the cost of nuclear energy is to increase the power density of the reactor core. Features of fuel design that enhance the potential for high power density are derived based on characteristics of ...

Feng, Dandong, Ph. D. Massachusetts Institute of Technology

2006-01-01T23:59:59.000Z

78

Design of annular fuel for high power density BWRs  

E-Print Network [OSTI]

Enabling high power density in the core of Boiling Water Reactors (BWRs) is economically profitable for existing or new reactors. In this work, we examine the potential for increasing the power density in BWR plants by ...

Morra, Paolo

2005-01-01T23:59:59.000Z

79

Apparatus for advancing a wellbore using high power laser energy  

DOE Patents [OSTI]

Delivering high power laser energy to form a borehole deep into the earth using laser energy. Down hole laser tools, laser systems and laser delivery techniques for advancement, workover and completion activities. A laser bottom hole assembly (LBHA) for the delivery of high power laser energy to the surfaces of a borehole, which assembly may have laser optics, a fluid path for debris removal and a mechanical means to remove earth.

Zediker, Mark S.; Land, Mark S.; Rinzler, Charles C.; Faircloth, Brian O.; Koblick, Yeshaya; Moxley, Joel F.

2014-09-02T23:59:59.000Z

80

High power laser workover and completion tools and systems  

DOE Patents [OSTI]

Workover and completion systems, devices and methods for utilizing 10 kW or more laser energy transmitted deep into the earth with the suppression of associated nonlinear phenomena. Systems and devices for the laser workover and completion of a borehole in the earth. These systems and devices can deliver high power laser energy down a deep borehole, while maintaining the high power to perform laser workover and completion operations in such boreholes deep within the earth.

Zediker, Mark S; Rinzler, Charles C; Faircloth, Brian O; Koblick, Yeshaya; Moxley, Joel F

2014-10-28T23:59:59.000Z

Note: This page contains sample records for the topic "high-power coherent terahertz" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

Metamaterial-Enhanced Nonlinear Terahertz Spectroscopy  

E-Print Network [OSTI]

We demonstrate large nonlinear terahertz responses in the gaps of metamaterial split ring resonators in several materials and use nonlinear THz transmission and THz-pump/THz-probe spectroscopy to study the nonlinear responses ...

Hwang, Harold Young

82

Development of terahertz quantum-cascade lasers  

E-Print Network [OSTI]

The terahertz or the far-infrared frequency range of the electromagnetic spectrum ( ... ) has historically been technologically underdeveloped despite having many potential applications, primarily due to lack of suitable ...

Kumar, Sushil, Ph. D. Massachusetts Institute of Technology

2007-01-01T23:59:59.000Z

83

Developments and advances in nonlinear terahertz spectroscopy  

E-Print Network [OSTI]

Nonlinear terahertz (THz) spectroscopy is a rapidly developing field, which is concerned with driving and observing nonlinear material responses in the THz range of the electromagnetic spectrum. In this thesis, I present ...

Brandt, Nathaniel Curran

2014-01-01T23:59:59.000Z

84

Direct detector for terahertz radiation  

DOE Patents [OSTI]

A direct detector for terahertz radiation comprises a grating-gated field-effect transistor with one or more quantum wells that provide a two-dimensional electron gas in the channel region. The grating gate can be a split-grating gate having at least one finger that can be individually biased. Biasing an individual finger of the split-grating gate to near pinch-off greatly increases the detector's resonant response magnitude over prior QW FET detectors while maintaining frequency selectivity. The split-grating-gated QW FET shows a tunable resonant plasmon response to FIR radiation that makes possible an electrically sweepable spectrometer-on-a-chip with no moving mechanical optical parts. Further, the narrow spectral response and signal-to-noise are adequate for use of the split-grating-gated QW FET in a passive, multispectral terahertz imaging system. The detector can be operated in a photoconductive or a photovoltaic mode. Other embodiments include uniform front and back gates to independently vary the carrier densities in the channel region, a thinned substrate to increase bolometric responsivity, and a resistive shunt to connect the fingers of the grating gate in parallel and provide a uniform gate-channel voltage along the length of the channel to increase the responsivity and improve the spectral resolution.

Wanke, Michael C. (Albuquerque, NM); Lee, Mark (Albuquerque, NM); Shaner, Eric A. (Albuquerque, NM); Allen, S. James (Santa Barbara, CA)

2008-09-02T23:59:59.000Z

85

Terahertz emission from black silicon M. Theuer,2  

E-Print Network [OSTI]

of different meth- ods for the generation of terahertz radiation have been devel- oped including pure optical-called photoconductive terahertz emitters and detectors, radiation-damaged silicon on sapphire or low- temperature grown of terahertz optics made out of silicon is that the copropagating infrared radiation is ab- sorbed sufficiently

86

Resonant terahertz radiation from layered superconductors: mechanisms of damping and structure of dynamic states.  

SciTech Connect (OSTI)

Intrinsic Josephson-junction stacks realized in high-temperature superconductors may generate powerful electromagnetic radiation in terahertz frequency range. A major challenge is to synchronize phase oscillations in many junctions. A promising way of efficient synchronization is to excite an internal cavity mode, with the frequency set by the stack lateral size. We discuss several issues relevant for this mechanism: (i) damping of the resonance mode due to radiation into free space and into the base crystal, (ii) mechanisms of coupling to the internal mode, (iii) structures and stability of coherent states.

Koshelev, A. E.; Bulaevskii, L. N.; Materials Science Division; LANL

2009-01-01T23:59:59.000Z

87

High-field half-cycle terahertz radiation from relativistic laser interaction with thin solid targets  

SciTech Connect (OSTI)

It is found that half-cycle terahertz (THz) pulses with the peak field over 100 MV/cm can be produced in ultrashort intense laser interactions with thin solid targets. These THz pulses are shown to emit from both the front and rear sides of the solid target and are attributed to the coherent transition radiation by laser-produced ultrashort fast electron bunches. After the primary THz pulses, subsequent secondary half-cycle pulses are generated while some refluxing electrons cross the vacuum-target interfaces. Since such strong THz radiation is well synchronized with the driving lasers, it is particularly suitable for applications in various pump-probe experiments.

Ding, W. J.; Koh, W. S. [A-STAR Institute of High Performance Computing, Singapore 138632 (Singapore)] [A-STAR Institute of High Performance Computing, Singapore 138632 (Singapore); Sheng, Z. M. [Key Laboratory for Laser Plasmas (MoE) and Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China) [Key Laboratory for Laser Plasmas (MoE) and Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China); SUPA, Department of Physics, University of Strathclyde, Glasgow G4 0NG (United Kingdom)

2013-11-11T23:59:59.000Z

88

Klamath Falls: High-Power Acoustic Well Stimulation Technology  

SciTech Connect (OSTI)

Acoustic well stimulation (AWS) technology uses high-power sonic waves from specific frequency spectra in an attempt to stimulate production in a damaged or low-production wellbore. AWS technology is one of the most promising technologies in the oil and gas industry, but it has proven difficult for the industry to develop an effective downhole prototype. This collaboration between Klamath Falls Inc. and the Rocky Mountain Oilfield Testing Center (RMOTC) included a series of tests using high-power ultrasonic tools to stimulate oil and gas production. Phase I testing was designed and implemented to verify tool functionality, power requirements, and capacity of high-power AWS tools. The purpose of Phase II testing was to validate the production response of wells with marginal production rates to AWS stimulation and to capture and identify any changes in the downhole environment after tool deployment. This final report presents methodology and results.

Black, Brian

2006-07-24T23:59:59.000Z

89

Catalytic Coherence  

E-Print Network [OSTI]

Due to conservation of energy we cannot directly turn a quantum system with a definite energy into a superposition of different energies. However, if we have access to an additional resource in terms of a system with a high degree of coherence, as for standard models of laser light, we can overcome this limitation. The question is to what extent coherence gets degraded when utilized. Here it is shown that coherence can be turned into a catalyst, meaning that we can use it repeatedly without ever diminishing its power to enable coherent operations. This finding stands in contrast to the degradation of other quantum resources, and has direct consequences for quantum thermodynamics, as it shows that latent energy that may be locked into superpositions of energy eigenstates can be released catalytically.

Johan Aberg

2014-10-20T23:59:59.000Z

90

Retroactive Coherence  

E-Print Network [OSTI]

In gravitational microlensing, interference visibility is established when the spectral resolution of the observation is less than the reciprocal of the time delay difference. Using high resolutionspectroscopy fringes will be visible at large path differences, even when the source emission is incoherent. This is possible because coherence can be established after interference has already occurred. Results of a laboratory test are presented which demonstrate this retroactive establishment of coherence.

J. B. Peterson

2002-03-15T23:59:59.000Z

91

Ultra high vacuum broad band high power microwave window  

DOE Patents [OSTI]

An improved high vacuum microwave window has been developed that utilizes high density polyethylene coated on two sides with SiOx, SiNx, or a combination of the two. The resultant low dielectric and low loss tangent window creates a low outgassing, low permeation seal through which broad band, high power microwave energy may be passed. No matching device is necessary and the sealing technique is simple. The features of the window are broad band transmission, ultra-high vacuum compatibility with a simple sealing technique, low voltage standing wave ratio, high power transmission and low cost.

Nguyen-Tuong, Viet (Seaford, VA); Dylla, III, Henry Frederick (Yorktown, VA)

1997-01-01T23:59:59.000Z

92

Ultra high vacuum broad band high power microwave window  

DOE Patents [OSTI]

An improved high vacuum microwave window has been developed that utilizes high density polyethylene coated on two sides with SiOx, SiNx, or a combination of the two. The resultant low dielectric and low loss tangent window creates a low outgassing, low permeation seal through which broad band, high power microwave energy may be passed. No matching device is necessary and the sealing technique is simple. The features of the window are broad band transmission, ultra-high vacuum compatibility with a simple sealing technique, low voltage standing wave ratio, high power transmission and low cost. 5 figs.

Nguyen-Tuong, V.; Dylla, H.F. III

1997-11-04T23:59:59.000Z

93

Science opportunities at high power accelerators like APT  

SciTech Connect (OSTI)

This paper presents applications of high power RF proton linear accelerators to several fields. Radioisotope production is an area in which linacs have already provided new isotopes for use in medical and industrial applications. A new type of spallation neutron source, called a long-pulse spallation source (LPSS), is discussed for application to neutron scattering and to the production and use of ultra-cold neutrons (UCN). The concept of an accelerator-driven, transmutation of nuclear waste system, based on high power RF linac technology, is presented along with its impact on spent nuclear fuels.

Browne, J.C.

1996-12-31T23:59:59.000Z

94

High-Power Electrochemical Storage Devices and Plug-in Hybrid...  

Broader source: Energy.gov (indexed) [DOE]

High-Power Electrochemical Storage Devices and Plug-in Hybrid Electric Vehicle Battery Development High-Power Electrochemical Storage Devices and Plug-in Hybrid Electric Vehicle...

95

High power light emitting diode based setup for photobleaching fluorescent impurities  

E-Print Network [OSTI]

High power light emitting diode based setup for photobleaching fluorescent impurities Tobias K be photobleached before final sample preparation. The instrument consists of high power light emitting diodes

Kaufman, Laura

96

Cooling System for the MERIT High-Power Target Experiment  

E-Print Network [OSTI]

and a remote PVSS supervision station connected via Ethernet. Operation Modes: Cooling of proximity cryogenicsCooling System for the MERIT High-Power Target Experiment Haug F., Pereira H., Silva P., Pezzetti M a free mercury jet inside a normal conducting pulsed 15 T capture solenoid magnet cooled with liquid

McDonald, Kirk

97

High-power, high-intensity laser propagation and interactions  

SciTech Connect (OSTI)

This paper presents overviews of a number of processes and applications associated with high-power, high-intensity lasers, and their interactions. These processes and applications include: free electron lasers, backward Raman amplification, atmospheric propagation of laser pulses, laser driven acceleration, atmospheric lasing, and remote detection of radioactivity. The interrelated physical mechanisms in the various processes are discussed.

Sprangle, Phillip [Plasma Physics Division, Naval Research Laboratory, Washington, DC 20375 (United States); Electrical and Computer Engineering and Physics, University of Maryland, College Park, Maryland 20740 (United States); Hafizi, Bahman [Plasma Physics Division, Naval Research Laboratory, Washington, DC 20375 (United States)

2014-05-15T23:59:59.000Z

98

A SIMPLIFIED ANALYSIS FOR HIGH POWER MICROWAVE BANDPASS FILTER STRUCTURES  

E-Print Network [OSTI]

and wireless diplexers. An exact analysis of the voltage/power distribution inside a filter involves the 3D is derived. This transformation is then used to relate the actual voltage distribution inside a transmissionA SIMPLIFIED ANALYSIS FOR HIGH POWER MICROWAVE BANDPASS FILTER STRUCTURES Apu Sivadas, Ming Yu

Yu, Ming

99

Trends in packaging of high power semiconductor laser bars  

SciTech Connect (OSTI)

Several different approaches to packaging high power diode laser bars for pumping solid state lasers or for direct diode laser applications are examined. The benefit and utility of each package is strongly dependent upon the fundamental optoelectronic properties of the individual diode laser bars. Factors which influence these properties are outlined and comparisons of packaging approaches for these materials are made.

Solarz, R.W.; Emanuel, M.A.; Skidmore, J.A.; Freitas, B.L.; Krupke, W.F.

1997-07-01T23:59:59.000Z

100

Tunable terahertz emission from Bi{<_2}Sr{<_2}CaCu{<_2}O{<_8+delta} mesa devices.  

SciTech Connect (OSTI)

We have measured coherent terahertz emission spectra from Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+{delta}} mesa devices as a function of temperature and mesa bias voltage. The emission frequency is found to be tunable by up to 12% by varying the temperature and bias voltage. We attribute the appearance of tunability to asymmetric boundaries at the top and bottom and the nonrectangular cross section of the mesas. This interpretation is consistent with numerical simulations of the dynamics of intrinsic Josephson junctions in the mesa. Easily tunable emission frequency may have important implications for the design of terahertz devices based on stacked intrinsic Josephson junctions.

Benseman, T. M.; Koshelev, A. E.; Gray, K. E.; Kwok, W.-K.; Welp, U.; Kadowaki, K.; Tachiki, M.; Yamamoto, T. (Materials Science Division); (Univ. Tsukuba); (Japan Atomic Energy Agency)

2011-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "high-power coherent terahertz" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

Parametric Study of Emerging High Power Accelerator Applications Using Accelerator Systems Model (ASM)  

E-Print Network [OSTI]

Parametric Study of Emerging High Power Accelerator Applications Using Accelerator Systems Model (ASM)

Berwald, D H; Myers, T J; Paulson, C C; Peacock, M A; Piaszczyk, C M; Rathke, J W; Piechowiak, E M

1996-01-01T23:59:59.000Z

102

Designing high power targets with computational fluid dynamics (CFD)  

SciTech Connect (OSTI)

High power liquid hydrogen (LH2) targets, up to 850 W, have been widely used at Jefferson Lab for the 6 GeV physics program. The typical luminosity loss of a 20 cm long LH2 target was 20% for a beam current of 100 ?A rastered on a square of side 2 mm on the target. The 35 cm long, 2500 W LH2 target for the Qweak experiment had a luminosity loss of 0.8% at 180 ?A beam rastered on a square of side 4 mm at the target. The Qweak target was the highest power liquid hydrogen target in the world and with the lowest noise figure. The Qweak target was the first one designed with CFD at Jefferson Lab. A CFD facility is being established at Jefferson Lab to design, build and test a new generation of low noise high power targets.

Covrig, S. D. [Thomas Jefferson National Laboratory, Newport News, VA 23606 (United States)

2013-11-07T23:59:59.000Z

103

High power l-band fast phase shifter  

SciTech Connect (OSTI)

Following successful testing of a concept prototype of a waveguide-based high power phase shifter, a design of a fast, high power device has been developed. The shifter uses two magnetically biased blocks of Yttrium Iron Garnet (YIG) positioned along the side walls of a rectangular waveguide. The cross-section of the waveguide is chosen to suppress unwanted RF modes that could otherwise compromise performance of the phase shifter. Static bias field in the YIG blocks is created by employing permanent magnets. Low inductance coils in the same magnetic circuit excite fast component of the bias field. Design of the device ensures effective heat extraction from the YIG blocks and penetration of the fast magnetic field inside the waveguide with minimum delay. This paper summarizes main steps in this development and gives brief description of the system.

Terechkine, I.; Khabiboulline, T.; Solyak, N.; /Fermilab

2008-10-01T23:59:59.000Z

104

Method and apparatus for improved high power impulse magnetron sputtering  

DOE Patents [OSTI]

A high power impulse magnetron sputtering apparatus and method using a vacuum chamber with a magnetron target and a substrate positioned in the vacuum chamber. A field coil being positioned between the magnetron target and substrate, and a pulsed power supply and/or a coil bias power supply connected to the field coil. The pulsed power supply connected to the field coil, and the pulsed power supply outputting power pulse widths of greater that 100 .mu.s.

Anders, Andre

2013-11-05T23:59:59.000Z

105

Active high-power RF switch and pulse compression system  

DOE Patents [OSTI]

A high-power RF switching device employs a semiconductor wafer positioned in the third port of a three-port RF device. A controllable source of directed energy, such as a suitable laser or electron beam, is aimed at the semiconductor material. When the source is turned on, the energy incident on the wafer induces an electron-hole plasma layer on the wafer, changing the wafer's dielectric constant, turning the third port into a termination for incident RF signals, and. causing all incident RF signals to be reflected from the surface of the wafer. The propagation constant of RF signals through port 3, therefore, can be changed by controlling the beam. By making the RF coupling to the third port as small as necessary, one can reduce the peak electric field on the unexcited silicon surface for any level of input power from port 1, thereby reducing risk of damaging the wafer by RF with high peak power. The switch is useful to the construction of an improved pulse compression system to boost the peak power of microwave tubes driving linear accelerators. In this application, the high-power RF switch is placed at the coupling iris between the charging waveguide and the resonant storage line of a pulse compression system. This optically controlled high power RF pulse compression system can handle hundreds of Megawatts of power at X-band.

Tantawi, Sami G. (San Mateo, CA); Ruth, Ronald D. (Woodside, CA); Zolotorev, Max (Mountain View, CA)

1998-01-01T23:59:59.000Z

106

High power test of a 57-MHz CW RFQ.  

SciTech Connect (OSTI)

High power heavy-ion drivers require a CW low-frequency RFQ for initial acceleration. The low frequency specifications required for heavy-ion acceleration typically result in large dimensions of the structure. By appropriate choice of the resonant structure for the Rare Isotope Accelerator (RIA) driver RFQ we have achieved moderate transverse dimensions of the cavity and high quality accelerating-focusing fields required for simultaneous acceleration of multiple-charge-state ion beams. In our application the RFQ must provide stable operation over a wide range of RF power levels to allow acceleration of masses from protons up to uranium. To demonstrate the technology and high-power operation we have built an engineering prototype of one-segment of the 57-MHz RFQ structure. The RFQ is designed as a 100% OFE copper structure and fabricated with a two-step furnace brazing process. The errors in the tip-to-tip distances of the vanes average less than 50 microns. The RF measurements show excellent electrical properties of the resonator with a measured intrinsic Q equal to 94% of the simulated value. In this paper we report final results of high-power tests.

Ostroumov, P. N.; Barcikowski, A.; Clifft, B.; Rusthoven, B.; Sharma, S.; Sharamentov, S. I.; Toter, W. F.; Rathke, J. W.; Vinogradov, N. E.; Schrage, D. L.; Advanced Energy Systems; Northern Illinois Univ.; TechSource

2006-01-01T23:59:59.000Z

107

Electron beam diagnostic for profiling high power beams  

DOE Patents [OSTI]

A system for characterizing high power electron beams at power levels of 10 kW and above is described. This system is comprised of a slit disk assembly having a multitude of radial slits, a conducting disk with the same number of radial slits located below the slit disk assembly, a Faraday cup assembly located below the conducting disk, and a start-stop target located proximate the slit disk assembly. In order to keep the system from over-heating during use, a heat sink is placed in close proximity to the components discussed above, and an active cooling system, using water, for example, can be integrated into the heat sink. During use, the high power beam is initially directed onto a start-stop target and after reaching its full power is translated around the slit disk assembly, wherein the beam enters the radial slits and the conducting disk radial slits and is detected at the Faraday cup assembly. A trigger probe assembly can also be integrated into the system in order to aid in the determination of the proper orientation of the beam during reconstruction. After passing over each of the slits, the beam is then rapidly translated back to the start-stop target to minimize the amount of time that the high power beam comes in contact with the slit disk assembly. The data obtained by the system is then transferred into a computer system, where a computer tomography algorithm is used to reconstruct the power density distribution of the beam.

Elmer, John W. (Danville, CA); Palmer, Todd A. (Livermore, CA); Teruya, Alan T. (Livermore, CA)

2008-03-25T23:59:59.000Z

108

COMPARATIVE STUDIES OF PROTON ACCELERATORS FOR HIGH POWER APPLICATIONS.  

SciTech Connect (OSTI)

There are many applications requiring high power proton accelerators of various kinds. However, each type of proton accelerator can only provide beam with certain characteristics, hence the match of accelerators and their applications need careful evaluation. In this talk, the beam parameters and performance limitations of linac, cyclotron, synchrotron, and FFAG accelerators are studied and their relative merits for application in neutron, muon, neutrino, and ADS will be assessed in terms of beam energy, intensity, bunch length, repetition rate, and beam power requirements. A possible match between the applications and the accelerator of choice is presented in a matrix form. The accelerator physics and technology issues and challenges involved will also be discussed.

WENG, W.T.

2006-05-29T23:59:59.000Z

109

Photonic microwave generation with high-power photodiodes  

E-Print Network [OSTI]

We utilize and characterize high-power, high-linearity modified uni-traveling carrier (MUTC) photodiodes for low-phase-noise photonic microwave generation based on optical frequency division. When illuminated with picosecond pulses from a repetition-rate-multiplied gigahertz Ti:sapphire modelocked laser, the photodiodes can achieve 10 GHz signal power of +14 dBm. Using these diodes, a 10 GHz microwave tone is generated with less than 500 attoseconds absolute integrated timing jitter (1 Hz-10 MHz) and a phase noise floor of -177 dBc/Hz. We also characterize the electrical response, amplitude-to-phase conversion, saturation and residual noise of the MUTC photodiodes.

Fortier, Tara M; Hati, Archita; Nelson, Craig; Taylor, Jennifer A; Fu, Yang; Campbell, Joe; Diddams, Scott A

2013-01-01T23:59:59.000Z

110

Optical power splitter for splitting high power light  

DOE Patents [OSTI]

An optical power splitter for the distribution of high-power light energy has a plurality of prisms arranged about a central axis to form a central channel. The input faces of the prisms are in a common plane which is substantially perpendicular to the central axis. A beam of light which is substantially coaxial to the central axis is incident on the prisms and at least partially strikes a surface area of each prism input face. The incident beam also partially passes through the central channel. 5 figs.

English, R.E. Jr.; Christensen, J.J.

1995-04-18T23:59:59.000Z

111

The Linac4 DTL Prototype: Low and High Power Measurements  

E-Print Network [OSTI]

The prototype of the Linac4 Drift Tube Linac (DTL) has undergone low power measurements in order to verify the RF coupling and to adjust the post-coupler lengths based on bead-pull and spectrum measurements. Following the installation at the test stand, the cavity has been subjected to high power operation at Linac4 and SPL duty cycles. Saturation effects and multipacting have been observed and linked to X-ray emission. Voltage holding is reported in the presence of magnetic fields from permanent magnet quadrupoles (PMQ) installed in the first drift tubes.

De Michele, G; Marques-Balula, J; Ramberger, S

2012-01-01T23:59:59.000Z

112

R&D ERL: High power RF systems  

SciTech Connect (OSTI)

The Energy Recovery Linac (ERL) project, now under construction at Brookhaven National Laboratory, requires two high power RF systems. The first RF system is for the 703.75 MHz superconducting electron gun. The RF power from this system is used to drive nearly half an Ampere of beam current to 2.5 MeV. There is no provision to recover any of this energy so the minimum amplifier power is 1 MW. It consists of 1 MW CW klystron, transmitter and power supplies, 1 MW circulator, 1 MW dummy load and a two-way power splitter. The second RF system is for the 703.75 MHz superconducting cavity. The system accelerates the beam to 54.7 MeV and recovers this energy. It will provide up to 50 kW of CW RF power to the cavity. It consists of 50 kW transmitter, circulator, and dummy load. This paper describes the two high power RF systems and presents the test data for both.

Zaltsman, A.

2010-01-15T23:59:59.000Z

113

High power RF systems for the BNL ERL project  

SciTech Connect (OSTI)

The Energy Recovery Linac (ERL) project, now under construction at Brookhaven National Laboratory, requires two high power RF systems. The first RF system is for the 703.75 MHz superconducting electron gun. The RF power from this system is used to drive nearly half an Ampere of beam current to 2 MeV. There is no provision to recover any of this energy so the minimum amplifier power is 1 MW. It consists of 1 MW CW klystron, transmitter and power supplies, 1 MW circulator, 1 MW dummy load and a two-way power splitter. The second RF system is for the 703.75 MHz superconducting cavity. The system accelerates the beam to 54.7 MeV and recovers this energy. It will provide up to 50 kW of CW RF power to the cavity. It consists of 50 kW transmitter, circulator, and dummy load. This paper describes the two high power RF systems and presents the test data for both.

Zaltsman, A.; Lambiase, R.

2011-03-28T23:59:59.000Z

114

Uppsala High Power Test Stand for ESS Spoke Cavities  

E-Print Network [OSTI]

The European Spallation Source (ESS) is one of the world’s most powerful neutron source. The ESS linac will accelerate 50mA pulse current of protons to 2.5GeV in 2.86 ms long pulses at a repetition rate of 14 Hz. It produces a beam with 5MW average power and 125MW peak power. ESS Spoke Linac consist of 28 superconducting spoke cavities, which will be developed by IPN Orsay, France. These Spoke Cavities will be tested at low power at IPN Orsay and high power testing will be performed in a high power test stand at Uppsala University. The test stand consists of tetrode based RF amplifier chain (352MHz, 350 kW) power and related RF distribution. Outputs of two tetrodes shall be combined with the hybrid coupler to produce 350 kW power. Preamplifier for a tetrode shall be solid state amplifier. As the spoke cavities are superconducting, the test stand also includes horizontal cryostat, Helium liquefier, test bunker etc. The paper describes features of the test stand in details.

Yogi, RA; Dancila, D; Gajewski, K; Hermansson, L; Noor, M; Wedberg, R; Santiago-Kern, R; Ekelöf, T; Lofnes, T; Ziemann, V; Goryashko, V; Ruber, R

2013-01-01T23:59:59.000Z

115

KT McDonald 4th High-Power Targetry Workshop May 2, 2011 1 The High-Power Target System  

E-Print Network [OSTI]

in system! Targets for 2-4 MW Proton Beams No such thing as "solid-target-only" at this power level. #12;KT that will be limited to less than 2 MW, static solid targets continue to be appealing. #12;KT McDonald 4th High-PowerKT McDonald 4th High-Power Targetry Workshop May 2, 2011 1 The High-Power Target System for a Muon

McDonald, Kirk

116

Colossal Absorption of Molecules Inside Single Terahertz Nanoantennas  

E-Print Network [OSTI]

Colossal Absorption of Molecules Inside Single Terahertz Nanoantennas Hyeong-Ryeol Park, Kwang Jun: Molecules have extremely small absorption cross sections in the terahertz range even under resonant to be enhanced by >103 accompanied by a colossal absorption coefficient of 170 000 cm-1 . Tens of nanograms

Park, Namkyoo

117

Porous polymer fibers for low-loss Terahertz guiding  

E-Print Network [OSTI]

of this fiber type is also compared to that of the equivalent sub-wavelength rod-in-the-air fiber the collective vibrational dynamics of a protein in liquid water by terahertz absorption spectroscopy", Protein. Kawase, "Laser terahertz-emission microscope for inspecting electrical faults in integrated circuits

Skorobogatiy, Maksim

118

Plasma characterization with terahertz timedomain measurements S. P. Jamisona)  

E-Print Network [OSTI]

Plasma characterization with terahertz time­domain measurements S. P. Jamisona) Department­domain spectral techniques are applied to the characterization of a He discharge plasma. Electro-optically sampling of the electric field of a quasi-unipolar terahertz pulse transmitted through the plasma has

Strathclyde, University of

119

Excitation of terahertz nanoantennas by Rabi waves  

SciTech Connect (OSTI)

Theoretical model of quantum dot ring, strongly coupled with classical electromagnetic field, is developed. We demonstrate, that tunnel current in the QD-ring has low-frequency component, excited by Rabi waves, propagating into the ring, and the ring can be considered as a candidate for role of terahertz magnetic loop antenna. The low-frequency current is inspired by the asymmetry of electron tunneling.

Slepyan, G. Ya.; Yerchak, Y. D.; Maksimenko, S. A. [Institute for Nuclear Problems, Belarus State University, Bobruiskaya 11, 220030 Minsk (Belarus); Hoffmann, A. [Institut fuer Festkoerperphysik, Technische Universitaet Berlin, Hardenbergstrasse 36, 10623 Berlin (Germany); Bass, F. G. [Department of Physics, Bar-Ilan University, 52900 Ramat-Gan (Israel)

2011-10-03T23:59:59.000Z

120

High-power single mode solid state laser with short wide unstable cavity: Misprints  

E-Print Network [OSTI]

1 High-power single mode solid state laser with short wide unstable cavity: Misprints D. Kouznetsov. Kouznetsov, J.-F. Bisson, K. Takaichi K. Ueda. High-power single mode solid state laser with short wide

Kouznetsov, Dmitrii

Note: This page contains sample records for the topic "high-power coherent terahertz" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

E-Print Network 3.0 - atr high-power mixed-oxide Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

75 A. R&D on a 50-kW, High-Efficiency, High-Power-Density, CO-Tolerant PEM Fuel Cell Stack System... of its high power density, quick start-up capability, and...

122

Failure modes in high-power lithium-ion batteries for use in hybrid electric vehicles  

E-Print Network [OSTI]

MODES IN HIGH-POWER LITHIUM-ION BATTERIES FOR USE IN HYBRIDof high-power lithium-ion batteries for hybrid electricthe development of lithium-ion batteries for hybrid electric

2001-01-01T23:59:59.000Z

123

IN-VEHICLE, HIGH-POWER ENERGY STORAGE SYSTEMS | Department of...  

Broader source: Energy.gov (indexed) [DOE]

IN-VEHICLE, HIGH-POWER ENERGY STORAGE SYSTEMS IN-VEHICLE, HIGH-POWER ENERGY STORAGE SYSTEMS 2013 DOE Hydrogen and Fuel Cells Program and Vehicle Technologies Program Annual Merit...

124

Develop high energy high power Li-ion battery cathode materials : a first principles computational study  

E-Print Network [OSTI]

as cathode materials for Li-ion battery. Physica B-CondensedHigh Energy High Power Li-ion Battery Cathode Materials AHigh Energy High Power Li-ion Battery Cathode Materials A

Xu, Bo; Xu, Bo

2012-01-01T23:59:59.000Z

125

High mobility ZnO nanowires for terahertz detection applications  

SciTech Connect (OSTI)

An oxide nanowire material was utilized for terahertz detection purpose. High quality ZnO nanowires were synthesized and field-effect transistors were fabricated. Electrical transport measurements demonstrated the nanowire with good transfer characteristics and fairly high electron mobility. It is shown that ZnO nanowires can be used as building blocks for the realization of terahertz detectors based on a one-dimensional plasmon detection configuration. Clear terahertz wave (?0.3?THz) induced photovoltages were obtained at room temperature with varying incidence intensities. Further analysis showed that the terahertz photoresponse is closely related to the high electron mobility of the ZnO nanowire sample, which suggests that oxide nanoelectronics may find useful terahertz applications.

Liu, Huiqiang [State Key Laboratory of Optoelectronic Materials and Technology, Sun Yat-Sen University, Guangdong, Guangzhou 510275 (China); State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials, Southwest University of Science and Technology, Sichuan, Mianyang 621010 (China); Peng, Rufang, E-mail: pengrufang@swust.edu.cn, E-mail: chusheng@mail.sysu.edu.cn; Chu, Shijin [State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials, Southwest University of Science and Technology, Sichuan, Mianyang 621010 (China); Chu, Sheng, E-mail: pengrufang@swust.edu.cn, E-mail: chusheng@mail.sysu.edu.cn [State Key Laboratory of Optoelectronic Materials and Technology, Sun Yat-Sen University, Guangdong, Guangzhou 510275 (China)

2014-07-28T23:59:59.000Z

126

Very low pressure high power impulse triggered magnetron sputtering  

DOE Patents [OSTI]

A method and apparatus are described for very low pressure high powered magnetron sputtering of a coating onto a substrate. By the method of this invention, both substrate and coating target material are placed into an evacuable chamber, and the chamber pumped to vacuum. Thereafter a series of high impulse voltage pulses are applied to the target. Nearly simultaneously with each pulse, in one embodiment, a small cathodic arc source of the same material as the target is pulsed, triggering a plasma plume proximate to the surface of the target to thereby initiate the magnetron sputtering process. In another embodiment the plasma plume is generated using a pulsed laser aimed to strike an ablation target material positioned near the magnetron target surface.

Anders, Andre; Andersson, Joakim

2013-10-29T23:59:59.000Z

127

Results of a preliminary, high power RF thruster test  

SciTech Connect (OSTI)

The objective of this program was to demonstrate a high power electrodeless, RF electric propulsion concept. This was successfully accomplished. No attempt was made to optimize the design of the thruster with regard to physical dimensions, mass flow, nozzle shape, operational frequency, or power level. Measurements made were chamber pressure, total and static pressures at the nozzle exit plane and exhaust tank pressure. Mass flows range from about 0.4 to 1 gm/sec and, assuming perfect gas relationships, specific impulses up to 580 sec were obtained. Typical chamber pressure was 300 torr exhausting to a tank pressure of about 10 torr. Working fluids used were argon, helium and mixtures of the two. No degration of the device was detected after 12 start/stop cycles, about three hours of total run time, and a maximum input power of 70 kW. 10 refs.

Brewer, L.; Karras, T.; Frind, G.; Holmes, D.G.

1989-01-01T23:59:59.000Z

128

New developments for high power electron beam equipment  

SciTech Connect (OSTI)

High power electron guns for industrial use work in the range of power of more than 10 kW up to 1200 kW. The only suitable principle for this purpose is that used in axial guns. Elements necessary for these EB guns and their design are described. The outstanding properties required for applications in production and R & D can only be achieved if the equipment is supplemented by a high voltage supply, beam guidance supply, vacuum generator and the various devices for observation, measurement and control. Standard rules for both the technical demands in application and dimensioning of some of the necessary components are explained. Special developments, such as high speed deflection, observation by BSE-camera and arc-free electron beam systems are also presented.

Melde, C.; Jaesch, G.; Maedler, E. [Von Ardenne Anlagentechnnik GmbH, Dresden (Germany)

1994-12-31T23:59:59.000Z

129

Applications of Ultrafast Terahertz Pulses for Intra-Excitonic Spectroscopy of Quasi-2D Electron-Hole Gases  

E-Print Network [OSTI]

Applications of Ultrafast Terahertz Pulses for Intra-the utilization of ultrafast terahertz (THz) pulses for theUltrafast Terahertz” 250-kHz Ti:Sapphire Regenerative Amplifier System Pulse

Kaindl, Robert A.; Carnahan, Marc A.; Hagele, Daniel; Chemla, D.S.

2006-01-01T23:59:59.000Z

130

Terahertz spectral signatures :measurement and detection LDRD project 86361 final report.  

SciTech Connect (OSTI)

LDRD Project 86361 provided support to upgrade the chemical and material spectral signature measurement and detection capabilities of Sandia National Laboratories using the terahertz (THz) portion of the electromagnetic spectrum, which includes frequencies between 0.1 to 10 THz. Under this project, a THz time-domain spectrometer was completed. This instrument measures sample absorption spectra coherently, obtaining both magnitude and phase of the absorption signal, and has shown an operating signal-to-noise ratio of 10{sub 4}. Additionally, various gas cells and a reflectometer were added to an existing high-resolution THz Fourier transform spectrometer, which greatly extend the functionality of this spectrometer. Finally, preliminary efforts to design an integrated THz transceiver based on a quantum cascade laser were begun.

Wanke, Michael Clement; Brener, Igal; Lee, Mark

2005-11-01T23:59:59.000Z

131

Emission of coherent THz-radiation from superconductors.  

SciTech Connect (OSTI)

Compact solid-state sources of terahertz (THz) radiation are being sought for sensing, imaging, and spectroscopy applications across the physical and biological sciences. We demonstrate that coherent continuous-wave THz radiation of sizable power can be extracted from intrinsic Josephson junctions in the layered high-temperature superconductor Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8}. In analogy to a laser cavity, the excitation of an electromagnetic cavity resonance inside the sample generates a macroscopic coherent state in which a large number of junctions are synchronized to oscillate in phase. The emission power is found to increase as the square of the number of junctions reaching values of 0.5 microwatt at frequencies up to 0.85 THz, and persists up to 50 kelvin. These results should stimulate the development of superconducting compact sources of THz radiation.

Ozyuzer, L.; Koshelev, A. E.; Kurter, C.; Gopalsami, N.; Li, Q.; Tachiki, M.; Kadowaki, K.; Yamamoto, T.; Minami, H.; Yamaguchi, H.; Tachiki, T.; Gray, K. E.; Kwok, W.- K.; Welp, U.; Izmir Inst. Tech.; Illinois Inst. Tech.; Univ. Tokyo; Univ. Tsukuba; Nat. Defence Academy

2007-11-23T23:59:59.000Z

132

Terahertz spectroscopy of two-dimensional subwavelength plasmonic structures  

SciTech Connect (OSTI)

The fascinating properties of plasmonic structures have had significant impact on the development of next generation ultracompact photonic and optoelectronic components. We study two-dimensional plasmonic structures functioning at terahertz frequencies. Resonant terahertz response due to surface plasmons and dipole localized surface plasmons were investigated by the state-of-the-art terahertz time domain spectroscopy (THz-TDS) using both transmission and reflection configurations. Extraordinary terahertz transmission was demonstrated through the subwavelength metallic hole arrays made from good conducting metals as well as poor metals. Metallic arrays m!lde from Pb, generally a poor metal, and having optically thin thicknesses less than one-third of a skin depth also contributed in enhanced THz transmission. A direct transition of a surface plasmon resonance from a photonic crystal minimum was observed in a photo-doped semiconductor array. Electrical controls of the surface plasmon resonances by hybridization of the Schottkey diode between the metallic grating and the semiconductor substrate are investigated as a function of the applied reverse bias. In addition, we have demonstrated photo-induced creation and annihilation of surface plasmons with appropriate semiconductors at room temperature. According to the Fano model, the transmission properties are characterized by two essential contributions: resonant excitation of surface plasmons and nonresonant direct transmission. Such plasmonic structures may find fascinating applications in terahertz imaging, biomedical sensing, subwavelength terahertz spectroscopy, tunable filters, and integrated terahertz devices.

Azad, Abul K [Los Alamos National Laboratory; Chen, Houtong [Los Alamos National Laboratory; Taylor, Antoinette [Los Alamos National Laboratory; O' Hara, John F [Los Alamos National Laboratory; Han, Jiaguang [OSU; Lu, Xinchao [OSU; Zhang, Weili [OSU

2009-01-01T23:59:59.000Z

133

Advanced, High Power, Next Scale, Wave Energy Conversion Device  

SciTech Connect (OSTI)

The project conducted under DOE contract DE?EE0002649 is defined as the Advanced, High Power, Next Scale, Wave Energy Converter. The overall project is split into a seven?stage, gated development program. The work conducted under the DOE contract is OPT Stage Gate III work and a portion of Stage Gate IV work of the seven stage product development process. The project effort includes Full Concept Design & Prototype Assembly Testing building on our existing PowerBuoy? technology to deliver a device with much increased power delivery. Scaling?up from 150kW to 500kW power generating capacity required changes in the PowerBuoy design that addressed cost reduction and mass manufacturing by implementing a Design for Manufacturing (DFM) approach. The design changes also focused on reducing PowerBuoy Installation, Operation and Maintenance (IO&M) costs which are essential to reducing the overall cost of energy. In this design, changes to the core PowerBuoy technology were implemented to increase capability and reduce both CAPEX and OPEX costs. OPT conceptually envisaged moving from a floating structure to a seabed structure. The design change from a floating structure to seabed structure would provide the implementation of stroke? unlimited Power Take?Off (PTO) which has a potential to provide significant power delivery improvement and transform the wave energy industry if proven feasible.

Mekhiche, Mike [Principal Investigator] [Principal Investigator; Dufera, Hiz [Project Manager] [Project Manager; Montagna, Deb [Business Point of Contact] [Business Point of Contact

2012-10-29T23:59:59.000Z

134

Probing Neutrino Oscillation Parameters using High Power Superbeam from ESS  

E-Print Network [OSTI]

A high-power neutrino superbeam experiment at the ESS facility has been proposed such that the source-detector distance falls at the second oscillation maximum, giving very good sensitivity to the measurement of CP violation. In this work, we explore the comparative physics reach of the experiment in terms of leptonic CP-violation, precision on atmospheric parameters, non-maximal theta23, and its octant for a variety of choices for the baselines. We also vary the neutrino vs. the anti-neutrino running time for the beam, and study its impact on the physics goals of the experiment. We find that for the determination of CP violation, 540 km baseline with 7 years of neutrino and 3 years of anti-neutrino (7nu+3nubar) run-plan performs the best and one expects a 4sigma sensitivity to CP violation for 59% of true values of deltaCP. The projected reach for the 200 km baseline with 7nu+3nubar run-plan is somewhat worse with 4sigma sensitivity for 51% of true values of deltaCP. On the other hand, for the discovery of a...

Agarwalla, Sanjib Kumar; Prakash, Suprabh

2014-01-01T23:59:59.000Z

135

High power linear pulsed beam annealer. [Patent application  

DOE Patents [OSTI]

A high power pulsed electron beam system for annealing semiconductors is comprised of an electron gun having a heated cathode, control grid and focus ring for confining the pulsed beam of electrons to a predetermined area, and a curved drift tube. The drift tube and an annular Faraday shield between the focus ring and the drift tube are maintained at a high positive voltage with respect to the cathode to accelerate electrons passing through the focus ring, thereby eliminating space charge limitations on the emission of electrons from said gun. A coil surrounding the curved drift tube provides a magnetic field which maintains the electron beam focused about the axis of the tube. The magnetic field produced by the coil around the curved tube imparts motion to electrons in a spiral path for shallow penetration of the electrons into a target. It also produces a scalloped profile of the electron beam. A second drift tube spaced a predetermined distance from the curved tube is positioned with its axis aligned with the axis of the first drift tube. The second drift tube and the target holder are maintained at a reference voltage between the cathode voltage and the curved tube voltage to decelerate the electrons. A second coil surrounding the second drift tube, maintains the electron beam focused about the axis of the second drift tube. The magnetic field of the second coil comprises the electron beam to the area of the semiconductor on the target holder.

Strathman, M.D.; Sadana, D.K.; True, R.B.

1980-11-26T23:59:59.000Z

136

High power KrF laser development at Los Alamos  

SciTech Connect (OSTI)

The objective of the high power laser development program at Los Alamos is to appraise the potential of the KrF laser as a driver for inertial confinement fusion (ICF), ultimately at energy levels that will produce high target gain (gain of order 100). A KrF laser system prototype, the 10-kJ Aurora laser, which is nearing initial system operation, will serve as a feasibility demonstration of KrF technology and system design concepts appropriate to large scale ICF driver systems. The issues of affordable cost, which is a major concern for all ICF drivers now under development, and technology scaling are also being examined. It is found that, through technology advances and component cost reductions, the potential exists for a KrF driver to achieve a cost goal in the neighborhood of $100 per joule. The authors suggest that the next step toward a multimegajoule laboratory microfusion facility (LMF) is an ''Intermediate Driver'' facility in the few hundred kilojoule to one megajoule range, which will help verify the scaling of driver technology and cost to an LMF size. An Intermediate Driver facility would also increase the confidence in the estimates of energy needed for an LMF and would reduce the risk in target performance. 5 refs., 4 figs., 1 tab.

McDonald, T.; Cartwright, D.; Fenstermacher, C.; Figueira, J.; Goldstone, P.; Harris, D.; Mead, W.; Rosocha, L.

1988-01-01T23:59:59.000Z

137

Plasma potential mapping of high power impulse magnetron sputtering discharges  

SciTech Connect (OSTI)

Pulsed emissive probe techniques have been used to determine the plasma potential distribution of high power impulse magnetron sputtering (HiPIMS) discharges. An unbalanced magnetron with a niobium target in argon was investigated for pulse length of 100 ?s at a pulse repetition rate of 100 Hz, giving a peak current of 170 A. The probe data were taken with a time resolution of 20 ns and a spatial resolution of 1 mm. It is shown that the local plasma potential varies greatly in space and time. The lowest potential was found over the target’s racetrack, gradually reaching anode potential (ground) several centimeters away from the target. The magnetic pre-sheath exhibits a funnel-shaped plasma potential resulting in an electric field which accelerates ions toward the racetrack. In certain regions and times, the potential exhibits weak local maxima which allow for ion acceleration to the substrate. Knowledge of the local E and static B fields lets us derive the electrons’ E×B drift velocity, which is about 105 m/s and shows structures in space and time.

Rauch, Albert; Mendelsberg, Rueben J.; Sanders, Jason M.; Anders, Andre

2011-12-20T23:59:59.000Z

138

Features of plasma glow in low pressure terahertz gas discharge  

SciTech Connect (OSTI)

Investigations of the low pressure (1–100 Torr) gas discharge in the powerful (1 kW) quasi-optical terahertz (0.55 THz) wave beams were made. An intense afterglow was observed after the end of gyrotron terahertz radiation pulse. Afterglow duration significantly exceeded radiation pulse length (8 ?s). This phenomenon could be explained by the strong dependence of the collisional-radiative recombination rate (that is supposed to be the most likely mechanism of electron losses from the low pressure terahertz gas discharge) on electron temperature.

Bratman, V. L.; Golubev, S. V.; Izotov, I. V.; Kalynov, Yu. K.; Koldanov, V. A.; Razin, S. V. [Institute of Applied Physics, Russian Academy of Sciences, Nizhny Novgorod 603950 (Russian Federation)] [Institute of Applied Physics, Russian Academy of Sciences, Nizhny Novgorod 603950 (Russian Federation); Litvak, A. G.; Sidorov, A. V.; Skalyga, V. A.; Zorin, V. G. [Institute of Applied Physics, Russian Academy of Sciences, Nizhny Novgorod 603950 (Russian Federation) [Institute of Applied Physics, Russian Academy of Sciences, Nizhny Novgorod 603950 (Russian Federation); Lobachevsky State University of Nizhny Novgorod (UNN), 23 Gagarina st., 603950 Nizhny Novgorod (Russian Federation)

2013-12-15T23:59:59.000Z

139

Terahertz radiation from a laser plasma filament  

SciTech Connect (OSTI)

By the use of two-dimensional particle-in-cell simulations, we clarify the terahertz (THz) radiation mechanism from a plasma filament formed by an intense femtosecond laser pulse. The nonuniform plasma density of the filament leads to a net radiating current for THz radiation. This current is mainly located within the pulse and the first cycle of the wakefield. As the laser pulse propagates, a single-cycle and radially polarized THz pulse is constructively built up forward. The single-cycle shape is mainly due to radiation damping effect.

Wu, H.-C.; Meyer-ter-Vehn, J. [Max-Planck-Institut fuer Quantenoptik, D-85748 Garching (Germany); Ruhl, H. [Department fuer Physik der Ludwig-Maximillians-Universitaet, Theresienstrasse 37A, D-80333 Muenchen (Germany); Sheng, Z.-M. [Institute of Plasma Studies, Department of Physics, Shanghai Jiaotong University, Shanghai 200240 (China); Beijing National Laboratory of Condensed Matter Physics, Institute of Physics, CAS, Beijing 100190 (China)

2011-03-15T23:59:59.000Z

140

Safety approaches for high power modular laser operation  

SciTech Connect (OSTI)

Approximately 20 years ago, a program was initiated at the Lawrence Livermore National Laboratory (LLNL) to study the feasibility of using lasers to separate isotopes of uranium and other materials. Of particular interest has been the development of a uranium enrichment method for the production of commercial nuclear power reactor fuel to replace current more expensive methods. The Uranium Atomic Vapor Laser Isotope Separation (U-AVLIS) Program has progressed to the point where a plant-scale facility to demonstrate commercial feasibility has been built and is being tested. The U-AVLIS Program uses copper vapor lasers which pump frequency selective dye lasers to photoionize uranium vapor produced by an electron beam. The selectively ionized isotopes are electrostatically collected. The copper lasers are arranged in oscillator/amplifier chains. The current configuration consists of 12 chains, each with a nominal output of 800 W for a system output in excess of 9 kW. The system requirements are for continuous operation (24 h a day, 7 days a week) and high availability. To meet these requirements, the lasers are designed in a modular form allowing for rapid change-out of the lasers requiring maintenance. Since beginning operation in early 1985, the copper lasers have accumulated over 2 million unit hours at a >90% availability. The dye laser system provides approximately 2.5 kW average power in the visible wavelength range. This large-scale laser system has many safety considerations, including high-power laser beams, high voltage, and large quantities ({approximately}3000 gal) of ethanol dye solutions. The Laboratory`s safety policy requires that safety controls be designed into any process, equipment, or apparatus in the form of engineering controls. Administrative controls further reduce the risk to an acceptable level. Selected examples of engineering and administrative controls currently being used in the U-AVLIS Program are described.

Handren, R.T.

1993-03-01T23:59:59.000Z

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141

Probing Neutrino Oscillation Parameters using High Power Superbeam from ESS  

E-Print Network [OSTI]

A high-power neutrino superbeam experiment at the ESS facility has been proposed such that the source-detector distance falls at the second oscillation maximum, giving very good sensitivity towards establishing CP violation. In this work, we explore the comparative physics reach of the experiment in terms of leptonic CP-violation, precision on atmospheric parameters, non-maximal theta23, and its octant for a variety of choices for the baselines. We also vary the neutrino vs. the anti-neutrino running time for the beam, and study its impact on the physics goals of the experiment. We find that for the determination of CP violation, 540 km baseline with 7 years of neutrino and 3 years of anti-neutrino (7nu+3nubar) run-plan performs the best and one expects a 5sigma sensitivity to CP violation for 48% of true values of deltaCP. The projected reach for the 200 km baseline with 7nu+3nubar run-plan is somewhat worse with 5sigma sensitivity for 34% of true values of deltaCP. On the other hand, for the discovery of a non-maximal theta23 and its octant, the 200 km baseline option with 7nu+3nubar run-plan performs significantly better than the other baselines. A 5sigma determination of a non-maximal theta23 can be made if the true value of sin^2theta23 lesssim 0.45 or sin^2theta23 gtrsim 0.57. The octant of theta23 could be resolved at 5sigma if the true value of sin^2theta23 lesssim 0.43 or gtrsim 0.59, irrespective of deltaCP.

Sanjib Kumar Agarwalla; Sandhya Choubey; Suprabh Prakash

2015-01-04T23:59:59.000Z

142

Optimization Studies for ISOL Type High-Powered Targets  

SciTech Connect (OSTI)

The research studied one-step and two-step Isotope Separation on Line (ISOL) targets for future radioactive beam facilities with high driver-beam power through advanced computer simulations. As a target material uranium carbide in the form of foils was used because of increasing demand for actinide targets in rare-isotope beam facilities and because such material was under development in ISAC at TRIUMF when this project started. Simulations of effusion were performed for one-step and two step targets and the effects of target dimensions and foil matrix were studied. Diffusion simulations were limited by availability of diffusion parameters for UCx material at reduced density; however, the viability of the combined diffusion?effusion simulation methodology was demonstrated and could be used to extract physical parameters such as diffusion coefficients and effusion delay times from experimental isotope release curves. Dissipation of the heat from the isotope-producing targets is the limiting factor for high-power beam operation both for the direct and two-step targets. Detailed target models were used to simulate proton beam interactions with the targets to obtain the fission rates and power deposition distributions, which were then applied in the heat transfer calculations to study the performance of the targets. Results indicate that a direct target, with specification matching ISAC TRIUMF target, could operate in 500-MeV proton beam at beam powers up to ~40 kW, producing ~8 1013 fission/s with maximum temperature in UCx below 2200 C. Targets with larger radius allow higher beam powers and fission rates. For the target radius in the range 9-mm to 30-mm the achievable fission rate increases almost linearly with target radius, however, the effusion delay time also increases linearly with target radius.

Remec, Igor [Oak Ridge National Laboratory] [Oak Ridge National Laboratory; Ronningen, Reginald Martin [Michigan State University] [Michigan State University

2013-09-24T23:59:59.000Z

143

Design, fabrication and characterization of terahertz quantum-well photodetectors  

E-Print Network [OSTI]

Terahertz (THz) photodetectors are important in the fully exploration and development of electromagnetic spectrum. However, a fast and sensitive THz photodetector ready for array integration is not available. A THz ...

Huang, Shengxi, S.M. Massachusetts Institute of Technology

2013-01-01T23:59:59.000Z

144

Characterization and analysis of highly diagonal Terahertz Quantum Cascade Lasers  

E-Print Network [OSTI]

The as yet unattained milestone of room-temperature operation is essential for establishing Terahertz Quantum Cascade Lasers (THz QCLs) as practical sources of THz radiation. Temperature performance is hypothesized to be ...

Chan, Chun Wang Ivan

2010-01-01T23:59:59.000Z

145

Terahertz imaging and quantum cascade laser based devices  

E-Print Network [OSTI]

The terahertz (THz) frequency range (f=0.3-10 THz, [lambda]=30-1000 lam) is much less technologically developed that the adjacent microwave and infrared frequency ranges, but offers several advantages for imaging applications: ...

Lee, Alan Wei Min

2010-01-01T23:59:59.000Z

146

High-Power Converters and AC Drives IEEE PESC2005 Tutorial  

E-Print Network [OSTI]

@ee.ryerson.ca http://www.ee.ryerson.ca/~bwu/ 2 High-Power Converters and AC Drives 1. Introduction 2. Cascaded H-Bridge Drives · High-Power Semiconductor Devices High-Power Converters and AC Drives Bin Wu 4High · Multilevel Voltage Source Inverters N dC Cascaded H-bridge (CHB) Inverter dC Two Level Inverter dC Flying

Wu, Bin

147

IEEE ELECTRON DEVICE LETTERS, VOL. 19, NO. 10, OCTOBER 1998 373 Terahertz Detector Utilizing  

E-Print Network [OSTI]

IEEE ELECTRON DEVICE LETTERS, VOL. 19, NO. 10, OCTOBER 1998 373 Terahertz Detector Utilizing Two. This result shows the potential for developing a new family of electronics devices--plasma wave electronics devices--operating at terahertz frequencies. Index Terms--HEMT, plasma wave electronics, terahertz de

Salama, Khaled

148

Propagation of terahertz pulses in photoexcited media: Analytical theory for layered systems  

E-Print Network [OSTI]

, Sweden Received 5 March 2007; accepted 18 May 2007; published online 13 July 2007 Optical pump the propagation of ultrashort terahertz pulses in photoexcited media. The transient terahertz wave form. Optical pump­terahertz probe OPTP experiments represent a powerful experimental method in which

KuÂ?el, Petr

149

Emission of terahertz radiation from SiC Jared H. Strait,a  

E-Print Network [OSTI]

for the generation of terahertz radiation. The nonlinear optical properties of various SiC polytypes have been previ the terahertz radiation dependence on the optical pump polarization, the pump angle of incidence, and the pump for terahertz emission. Given its material hard- ness, high optical damage threshold, small optical losses

Afshari, Ehsan

150

Maximal Privacy without Coherence  

E-Print Network [OSTI]

Privacy is a fundamental feature of quantum mechanics. A coherently transmitted quantum state is inherently private. Remarkably, coherent quantum communication is not a prerequisite for privacy: there are quantum channels ...

Leung, Debbie

151

Computed tomography image using sub-terahertz waves generated from a high-T{sub c} superconducting intrinsic Josephson junction oscillator  

SciTech Connect (OSTI)

A computed tomography (CT) imaging system using monochromatic sub-terahertz coherent electromagnetic waves generated from a device constructed from the intrinsic Josephson junctions in a single crystalline mesa structure of the high-T{sub c} superconductor Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+?} was developed and tested on three samples: Standing metallic rods supported by styrofoam, a dried plant (heart pea) containing seeds, and a plastic doll inside an egg shell. The images obtained strongly suggest that this CT imaging system may be useful for a variety of practical applications.

Kashiwagi, T., E-mail: kashiwagi@ims.tsukuba.ac.jp; Minami, H.; Kadowaki, K. [Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba (Japan); Division of Materials Science, Faculty of Pure and Applied Sciences, University of Tsukuba, 1-1-1, Tennodai, Tsukuba, Ibaraki 305-8573 (Japan); Nakade, K.; Saiwai, Y.; Kitamura, T.; Watanabe, C.; Ishida, K.; Sekimoto, S.; Asanuma, K.; Yasui, T.; Shibano, Y. [Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba (Japan); Tsujimoto, M. [Department of Electronic Science and Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510 (Japan); Yamamoto, T. [Wide Bandgap Materials Group, Optical and Electronic Materials Unit, Environment and Energy Materials Division, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); Markovi?, B. [Faculty of Sciences, University of Montenegro, George Washington Str., 81000 Podgorica (Montenegro); Mirkovi?, J. [Faculty of Science, University of Montenegro, and CETI, Put Radomira Ivanovica, 81000 Podgorica (Montenegro); Klemm, R. A. [Department of Physics, University of Central Florida, 4000 Central Florida Blvd., Orlando, Florida 32816-2385 (United States)

2014-02-24T23:59:59.000Z

152

DESY, February 2001, TESLA Report 2001-04 Concept of the High Power e  

E-Print Network [OSTI]

DESY, February 2001, TESLA Report 2001-04 Concept of the High Power e± Beam Dumps for TESLA W. Bialowons, M. Maslov, M. Schmitz, V. Sytchev #12;1 Concept of the High Power e± Beam Dumps for TESLA W............................................................................................................... 19 #12;2 1 Introduction The TESLA accelerator is equipped with quite a number of extraction lines

153

A Thrust Stand for High-power Steady-state Plasma Thrusters L.D. Cassady,  

E-Print Network [OSTI]

of an inverted-pendulum thrust stand to measure thrust for high-power steady- state plasma thrusters is presentedA Thrust Stand for High-power Steady-state Plasma Thrusters L.D. Cassady, A.D. Kodys, and E Department Princeton University, Princeton, New Jersey 08544 (Dated: July 18, 2002) The operation

Choueiri, Edgar

154

Thermal Effects on Inverted Pendulum Thrust Stands for Steady-state High-power Plasma Thrusters  

E-Print Network [OSTI]

Thermal Effects on Inverted Pendulum Thrust Stands for Steady-state High-power Plasma Thrusters A and Aerospace Engineering Department Princeton University, Princeton, New Jersey 08544 AIAA-2003-4842§ July 22, 2003 Abstract Thermal effects on direct measurements of the thrust produced by steady-state, high-power

Choueiri, Edgar

155

Simulation Model of Common-Mode Chokes for High-Power Applications  

E-Print Network [OSTI]

Simulation Model of Common-Mode Chokes for High-Power Applications A. Muetze C. R. Sullivan Found;Simulation Model of Common-Mode Chokes for High-Power Applications Charles R. Sullivan Annette Muetze Thayer simulation models for nanocrystalline cores, and compare the results to experimental measurements. We also

156

Terahertz graphene lasers: Injection versus optical pumping  

SciTech Connect (OSTI)

We analyze the formation of nonequilibrium states in optically pumped graphene layers and in forward-biased graphene structures with lateral p-i-n junctions and consider the conditions of population inversion and lasing. The model used accounts for intraband and interband relaxation processes as well as deviation of the optical phonon system from equilibrium. As shown, optical pumping suffers from a significant heating of both the electron-hole plasma and the optical phonon system, which can suppress the formation of population inversion. In the graphene structures with p-i-n junction, the injected electrons and holes have relatively low energies, so that the effect of cooling can be rather pronounced, providing a significant advantage of the injection pumping in realization of graphene terahertz lasers.

Ryzhii, Victor; Otsuji, Taiichi [Research Institute for Electrical Communication, Tohoku University, Sendai 980-8577 (Japan); Ryzhii, Maxim [Computational Nanoelectronics Laboratory, University of Aizu, Aizu-Wakamatsu 965-8580 (Japan); Mitin, Vladimir [Department of Electrical Engineering, University at Buffalo, SUNY, Buffalo, New York 14260-1920 (United States)

2013-12-04T23:59:59.000Z

157

Plasma Physics Challenges of MMPlasma Physics Challenges of MM--toto--THz and High Power MicrowaveTHz and High Power Microwave  

E-Print Network [OSTI]

Solid StateSolid State Microwave Power ElectronicsMicrowave Power Electronics · Both convert kinetic Devices (Avg) Vacuum HPM (Peak) Solid State Lasers (Peak) Solid State Devices (Avg) Power(W) (Single ...BUT ... For f > 100 GHz VEDs frontier 1/f2P High power limit for Solid State 1/f 2 and HPM Frontier

158

High-Efficiency and High-Power CMOS Power Amplifiers for Millimeter-Wave Applications /  

E-Print Network [OSTI]

K. Han, “W-band, 5W Solid-State Power Amplifier/Combiner,”materials have made high-power solid-state power amplifiersCMOS RF power amplifier for GSM-EDGE,” IEEE J. Solid-State

Agah, Amir

2013-01-01T23:59:59.000Z

159

Vehicle Technologies Office Merit Review 2014: High Energy High Power Battery Exceeding PHEV-40 Requirements  

Broader source: Energy.gov [DOE]

Presentation given by [company name] at 2014 DOE Hydrogen and Fuel Cells Program and Vehicle Technologies Office Annual Merit Review and Peer Evaluation Meeting about high energy high power battery...

160

Electrical characterization and modelling of round spiral supercapacitors for high power applications  

E-Print Network [OSTI]

Electrical characterization and modelling of round spiral supercapacitors for high power of supercapacitors under railway and electrical traction constraints. Electrical model parameters according techniques and instrumentations. Nowadays several electrical characterization methods exist. We have chosen

Paris-Sud XI, Université de

Note: This page contains sample records for the topic "high-power coherent terahertz" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

Detection of nanosecond-scale, high power THz pulses with a field effect transistor  

SciTech Connect (OSTI)

We demonstrate detection and resolution of high power, 34 ns free electron laser pulses using a rectifying field effect transistor. The detector remains linear up to an input power of 11 {+-} 0.5 W at a pulse energy of 20 {+-} 1 {mu}J at 240 GHz. We compare its performance to a protected Schottky diode, finding a shorter intrinsic time constant. The damage threshold is estimated to be a few 100 W. The detector is, therefore, well-suited for characterizing high power THz pulses. We further demonstrate that the same detector can be used to detect low power continuous-wave THz signals with a post detection limited noise floor of 3.1 {mu}W/{radical}(Hz). Such ultrafast, high power detectors are important tools for high power and high energy THz facilities such as free electron lasers.

Preu, S. [Physics Department and Institute for Terahertz Science and Technology, University of California, Santa Barbara, California 93106 (United States); Materials Department, University of California, Santa Barbara, California 93106 (United States); Chair for Applied Physics, University of Erlangen-Nuremberg, 91058 Erlangen (Germany); Lu, H.; Gossard, A. C. [Materials Department, University of California, Santa Barbara, California 93106 (United States); Sherwin, M. S. [Physics Department and Institute for Terahertz Science and Technology, University of California, Santa Barbara, California 93106 (United States)

2012-05-15T23:59:59.000Z

162

NEUTRONIC AND THERMAL HYDRAULIC DESIGNS OF ANNULAR FUEL FOR HIGH POWER DENSITY BWRS  

E-Print Network [OSTI]

As a promising new fuel for high power density light water reactors, the feasibility of using annular fuel for BWR services is explored from both thermal hydraulic and neutronic points of view. Keeping the bundle size ...

Morra, P.

163

Graphene surface emitting terahertz laser: Diffusion pumping concept  

SciTech Connect (OSTI)

We suggest a concept of a tunable graphene-based terahertz (THz) surface emitting laser with diffusion pumping. We employ significant difference in the electronic energy gap of graphene and a typical wide-gap semiconductor, and demonstrate that carriers generated in the semiconductor can be efficiently captured by graphene resulting in population inversion and corresponding?THz lasing from graphene. We develop design principles for such a laser and estimate its performance. We predict up to 50?W/cm{sup 2} terahertz power output for 100?kW/cm{sup 2} pump power at frequency around 10?THz at room temperature.

Davoyan, Arthur R., E-mail: davoyan@seas.upenn.edu [Kotelnikov Institute of Radio Engineering and Electronics (Saratov Branch), Russian Academy of Sciences, Saratov 410019, Russia and Department of Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104 (United States); Morozov, Mikhail Yu.; Popov, Vyacheslav V. [Kotelnikov Institute of Radio Engineering and Electronics (Saratov Branch), Russian Academy of Sciences, Saratov 410019 (Russian Federation)] [Kotelnikov Institute of Radio Engineering and Electronics (Saratov Branch), Russian Academy of Sciences, Saratov 410019 (Russian Federation); Satou, Akira; Otsuji, Taiichi [Research Institute of Electrical Communication (RIEC), Tohoku University, Sendai, Miyagi 980-8577 (Japan)] [Research Institute of Electrical Communication (RIEC), Tohoku University, Sendai, Miyagi 980-8577 (Japan)

2013-12-16T23:59:59.000Z

164

Generalized coherent states  

E-Print Network [OSTI]

In the coherent state of the harmonic oscillator, the probability density is that of the ground state subjected to an oscillation along a classical trajectory. Senitzky and others pointed out that there are states of the harmonic oscillator corresponding to an identical oscillatory displacement of the probability density of any energy eigenstate. These generalizations of the coherent state are rarely discussed, yet they furnish an interesting set of quantum states of light that combine features of number states and coherent states. Here we give an elementary account of the quantum optics of generalized coherent states.

T. G. Philbin

2013-12-18T23:59:59.000Z

165

Method and apparatus for delivering high power laser energy over long distances  

DOE Patents [OSTI]

Systems, devices and methods for the transmission of 1 kW or more of laser energy deep into the earth and for the suppression of associated nonlinear phenomena. Systems, devices and methods for the laser drilling of a borehole in the earth. These systems can deliver high power laser energy down a deep borehole, while maintaining the high power to advance such boreholes deep into the earth and at highly efficient advancement rates.

Zediker, Mark S; Rinzler, Charles C; Faircloth, Brian O; Koblick, Yeshaya; Moxley, Joel F

2013-08-20T23:59:59.000Z

166

Methods for enhancing the efficiency of creating a borehole using high power laser systems  

DOE Patents [OSTI]

Methods for utilizing 10 kW or more laser energy transmitted deep into the earth with the suppression of associated nonlinear phenomena to enhance the formation of Boreholes. Methods for the laser operations to reduce the critical path for forming a borehole in the earth. These methods can deliver high power laser energy down a deep borehole, while maintaining the high power to perform operations in such boreholes deep within the earth.

Zediker, Mark S.; Rinzler, Charles C.; Faircloth, Brian O.; Koblick, Yeshaya; Moxley, Joel F.

2014-06-24T23:59:59.000Z

167

Method and system for advancement of a borehole using a high power laser  

DOE Patents [OSTI]

There is provided a system, apparatus and methods for the laser drilling of a borehole in the earth. There is further provided with in the systems a means for delivering high power laser energy down a deep borehole, while maintaining the high power to advance such boreholes deep into the earth and at highly efficient advancement rates, a laser bottom hole assembly, and fluid directing techniques and assemblies for removing the displaced material from the borehole.

Moxley, Joel F.; Land, Mark S.; Rinzler, Charles C.; Faircloth, Brian O.; Zediker, Mark S.

2014-09-09T23:59:59.000Z

168

A terahertz-driven electron gun  

E-Print Network [OSTI]

Electron sources at keV-MeV energies are indispensable for applications such as ultrafast electron diffraction, x-ray generation, and electron energy-loss spectroscopy. However, the accessibility and size of current accelerators based on radio-frequency (RF) technology are limited by the achievable electric fields. Terahertz based accelerators promise unprecedented compactness compared to current RF accelerators due to the intense electric fields that can be applied in the accelerating structures. Here, electron bunches of 50 fC from a flat copper photocathode are accelerated from rest to a mean energy of 18 eV by a single-cycle THz field with peak electric field gradient of 72 MV/m at 1 kHz repetition rate. Scaling of the THz field into the gigavolt per meter regime would translate to electron energies of ~100 keV. Furthermore, in combination with the recent demonstration of a THz linear accelerator (linac), this is a milestone toward a millimeter- to centimeter-scale relativistic electron source.

Huang, W Ronny; Ravi, Koustuban; Hong, Kyung-Han; Wong, Liang Jie; Keathley, Phillip D; Fallahi, A; Zapata, Luis; Kärtner, Franz X

2014-01-01T23:59:59.000Z

169

Project of Rotating Carbon High-Power Neutron Target. Research of Graphite Properties for Production of High Intensity Neutron Source  

E-Print Network [OSTI]

Project of Rotating Carbon High-Power Neutron Target. Research of Graphite Properties for Production of High Intensity Neutron Source

Gubin, K V; Bak, P A; Kot, N K; Logatchev, P V

2001-01-01T23:59:59.000Z

170

Method for large and rapid terahertz imaging  

DOE Patents [OSTI]

A method of large-scale active THz imaging using a combination of a compact high power THz source (>1 watt), an optional optical system, and a camera for the detection of reflected or transmitted THz radiation, without the need for the burdensome power source or detector cooling systems required by similar prior art such devices. With such a system, one is able to image, for example, a whole person in seconds or less, whereas at present, using low power sources and scanning techniques, it takes several minutes or even hours to image even a 1 cm.times.1 cm area of skin.

Williams, Gwyn P.; Neil, George R.

2013-01-29T23:59:59.000Z

171

High power single-crystal fiber CW 946 nm laser and blue generation based on Rubidium-doped PPKTP  

E-Print Network [OSTI]

for high power, continuous wave and polarized laser at 946 nm (fig1.c). We demonstrate a polarized laser. Laurell, "High-power, continous-wave, second harmonic generation at 532 nm in periodically poled KTiOPO4(b)(a) (c) High power single-crystal fiber CW 946 nm laser and blue generation based on Rubidium

Boyer, Edmond

172

Ultra-Fast Photodiodes for Terahertz Generation E. Rouvalis1  

E-Print Network [OSTI]

Ultra-Fast Photodiodes for Terahertz Generation E. Rouvalis1 , C. C. Renaud1 and A. J. Seeds1 1 Photodiode is realised as a broadband and high-efficiency photomixer while the frequency response advantage-power photomixers is essential. 2. Travelling-Wave Uni-Travelling Carrier Photodiode (TW-UTC-PD). Bandwidth

Haddadi, Hamed

173

Scanning Probe Laser Terahertz Emission Microscopy System Ryotaro INOUE  

E-Print Network [OSTI]

is irradiated from the vicinity of the surface by an optical-fiber probe. The large numerical aperture pulse is irradiated to the sample surface by a commercial optical-fiber probe (LWP-LEN-SM, Cascade the sample surface, and terahertz emission from the locally photoexcited area is obtained. Using an optical-fiber

Tonouchi, Masayoshi

174

Application of nanoporous silicon substrates for terahertz spectroscopy  

E-Print Network [OSTI]

molecule," Spectrochim. Acta 61, 2741­2746 (2005). 4. M. Kutteruf, C. Brown, L. Iwaki, M. Campbell, T 1. M. van Exter, C. Fattinger, and D. Grischkowsky, "Terahertz time-domain spectroscopy of water acid molecule," J. Raman Spectrosc. 14, 347­352 (1983). 7. E. J. Heilweil and D. F. Plusquellic

Murphy, Thomas E.

175

Radiation Characteristics of Tunable Graphennas in the Terahertz Band  

E-Print Network [OSTI]

, KTH Royal Institute of Technology, 16640 Kista, Sweden 5Department of Electrical Engineering in size have been predicted to radiate electromagnetic waves at the terahertz band. In this work frequencies, in the optical range. Due to the expectedly very limited power of nanosystems, the low mobility

Politècnica de Catalunya, Universitat

176

High-resolution terahertz atmospheric water vapor continuum measurements  

E-Print Network [OSTI]

High-resolution terahertz atmospheric water vapor continuum measurements David M. Slocum,* Thomas M such as pollution monitoring and the detection of energetic chemicals using remote sensing over long path lengths through the atmosphere. Although there has been much attention to atmospheric effects over narrow

Massachusetts at Lowell, University of

177

Reflection type of terahertz imaging system using a high-T{sub c} superconducting oscillator  

SciTech Connect (OSTI)

A reflection type of imaging system is shown at sub-terahertz frequencies generated from high-T{sub c} superconducting intrinsic Josephson junction mesa structures fabricated by single crystalline Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+?} to demonstrate how the sub-terahertz imaging technique using monochromatic radiation is powerful and unique for the variety of practical applications. Several examples are discussed in detail and are compared to other terahertz imaging systems.

Kashiwagi, T.; Minami, H.; Kadowaki, K. [Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1, Tennodai, Tsukuba, Ibaraki 305-8571 (Japan); Division of Materials Science, Faculty of Pure and Applied Sciences, University of Tsukuba, 1-1-1, Tennodai, Tsukuba, Ibaraki 305-8573 (Japan); Nakade, K.; Saiwai, Y.; Kitamura, T.; Watanabe, C.; Ishida, K.; Sekimoto, S.; Asanuma, K.; Yasui, T.; Shibano, Y. [Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1, Tennodai, Tsukuba, Ibaraki 305-8571 (Japan); Markovi?, B.; Mirkovi?, J. [Faculty of Sciences, University of Montenegro, George Washington Str., 81000 Podgorica (Montenegro); Tsujimoto, M. [Department of Electronic Science and Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510 (Japan); Yamamoto, T. [National Institute for Materials Science, Wide Bandgap Materials Group, Optical and Electronic Materials Unit, Environment and Energy Materials Division, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan)

2014-01-13T23:59:59.000Z

178

Design of a terahertz parametric oscillator based on a resonant cavity in a terahertz waveguide  

SciTech Connect (OSTI)

We demonstrate ns-pulsed pumping of terahertz (THz) parametric oscillations in a quasi-triply resonant cavity in a THz waveguide. The THz waves, down converted through parametric interactions between the pump and signal waves at telecom frequencies, are confined to a GaP single mode ridge waveguide. By combining the THz waveguide with a quasi-triply resonant cavity, the nonlinear interactions can be enhanced. A low threshold pump intensity for parametric oscillations can be achieved in the cavity waveguide. The THz output power can be maximized by optimizing the quality factors of the cavity so that an optical to THz photon conversion efficiency, ?{sub p}, of 0.35, which is near the quantum-limit level, can be attained. The proposed THz optical parametric oscillator can be utilized as an efficient and monochromatic THz source.

Saito, K., E-mail: k-saito@material.tohoku.ac.jp; Oyama, Y. [Department of Materials Science, Graduate School of Engineering, Tohoku University, 6-6-11-1021, Aoba-ku, 980-8579 Sendai (Japan); Tanabe, T. [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1, Katahira, Aoba-ku, 980-8577 Sendai (Japan)

2014-07-28T23:59:59.000Z

179

Theory of a laser-plasma method for detecting terahertz radiation  

SciTech Connect (OSTI)

A theory is developed for calculating the spectrum and the shape of a terahertz wave packet from the temporal profile of the energy of the second harmonic of the laser field generated during nonlinear interaction of laser and terahertz pulses in an optical-breakdown plasma. The spectral and temporal characteristics of the second-harmonic envelope and a terahertz pulse are shown to coincide only for short laser pulses. For long laser pulses, the second-harmonic spectral line shifts to the red and its temporal profile is determined by the time integral of the electric field of terahertz radiation.

Frolov, A. A., E-mail: frolov@ihed.ras.ru [Russian Academy of Sciences, Joint Institute for High Temperatures (Russian Federation); Borodin, A. V.; Esaulkov, M. N.; Kuritsyn, I. I.; Shkurinov, A. P. [Moscow State University (Russian Federation)

2012-06-15T23:59:59.000Z

180

Terahertz wave emission from intrinsic Josephson junctions in high-T{sub c} superconductors.  

SciTech Connect (OSTI)

Recently, we experimentally demonstrated that rectangular mesa structures of intrinsic Josephson junctions (IJJ) in Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+d} (Bi2212) can be used as a compact solid-state generator of continuous, coherent and polarized terahertz (THz) radiation. In the present work, we will exhibit tall mesas (over 600 junctions) which were fabricated using UV lithography, e-beam lithography with photoresist and e-beam lithography with a Ti selective etching technique. We will present measurements of the c-axis resistance as a function of temperature and of current-voltage characteristics of THz emitting mesas with lateral sizes ranging from 30 x 300 to 100 x 300 {micro}m{sup 2}. Furthermore, we will discuss the dependence of the characteristics of the mesa structures on the oxygen doping level of the Bi2212 crystals. We will also experimentally show that the voltage-frequency relation of the ac Josephson effect has to match the cavity resonance for successful emission.

Ozyuzer, L.; Simsek, Y.; Koseoglu, H.; Turkoglu, F.; Kurter, C.; Welp, U.; Koshelev, A. E.; Gray, K. E.; Kwok, W. K.; Yamamoto, T.; Kadowaki, K.; Koval, Y.; Wang, H. B.; Muller, P.; Materials Science Division; Izmir Inst. of Tech.; Univ. of Erlangen-Nurnberg; Univ. of Tsukuba; National Inst. for Materials Science

2009-10-20T23:59:59.000Z

Note: This page contains sample records for the topic "high-power coherent terahertz" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

Graphene vertical hot-electron terahertz detectors  

SciTech Connect (OSTI)

We propose and analyze the concept of the vertical hot-electron terahertz (THz) graphene-layer detectors (GLDs) based on the double-GL and multiple-GL structures with the barrier layers made of materials with a moderate conduction band off-set (such as tungsten disulfide and related materials). The operation of these detectors is enabled by the thermionic emissions from the GLs enhanced by the electrons heated by incoming THz radiation. Hence, these detectors are the hot-electron bolometric detectors. The electron heating is primarily associated with the intraband absorption (the Drude absorption). In the frame of the developed model, we calculate the responsivity and detectivity as functions of the photon energy, GL doping, and the applied voltage for the GLDs with different number of GLs. The detectors based on the cascade multiple-GL structures can exhibit a substantial photoelectric gain resulting in the elevated responsivity and detectivity. The advantages of the THz detectors under consideration are associated with their high sensitivity to the normal incident radiation and efficient operation at room temperature at the low end of the THz frequency range. Such GLDs with a metal grating, supporting the excitation of plasma oscillations in the GL-structures by the incident THz radiation, can exhibit a strong resonant response at the frequencies of several THz (in the range, where the operation of the conventional detectors based on A{sub 3}B{sub 5} materials, in particular, THz quantum-well detectors, is hindered due to a strong optical phonon radiation absorption in such materials). We also evaluate the characteristics of GLDs in the mid- and far-infrared ranges where the electron heating is due to the interband absorption in GLs.

Ryzhii, V., E-mail: v-ryzhii@riec.tohoku.ac.jp [Research Institute for Electrical Communication, Tohoku University, Sendai 980-8577 (Japan); Center for Photonics and Infrared Engineering, Bauman Moscow State Technical University and Institute of Ultra High Frequency Semiconductor Electronics, Russian Academy of Sciences, Moscow 111005 (Russian Federation); Satou, A.; Otsuji, T. [Research Institute for Electrical Communication, Tohoku University, Sendai 980-8577 (Japan); Ryzhii, M. [Department of Computer Science and Engineering, University of Aizu, Aizu-Wakamatsu 965-8580 (Japan); Mitin, V. [Department of Electrical Engineering, University at Buffalo, Buffalo, New York 1460-1920 (United States); Shur, M. S. [Departments of Electrical, Electronics, and Systems Engineering and Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States)

2014-09-21T23:59:59.000Z

182

Single mode terahertz quantum cascade amplifier  

E-Print Network [OSTI]

coherent radiation with high signal to noise ratio are required. In fact such devices have already been demonstrated in the master-oscillator power amplifier scheme5 as well as a gain-switched amplifier for ultrafast pulses6. For the master... the amplification of short pulses. So in principle, the straightforward way to achieve a quantum casade (QC) amplifier would require a proper antireflective (AR) coating on the facet to fully suppress the feedback, thus the bare cavity gain could be exploited...

Ren, Y; Wallis, R.; Shah, Y. D.; Jessop, D. S.; Degl'Innocenti, R.; Klimont, A.; Kamboj, V.; Beere, H. E.; Ritchie, D. A.

2014-10-06T23:59:59.000Z

183

Space reactor/Stirling cycle systems for high power Lunar applications  

SciTech Connect (OSTI)

NASA`s Space Exploration Initiative (SEI) has proposed the use of high power nuclear power systems on the lunar surface as a necessary alternative to solar power. Because of the long lunar night ({approximately} 14 earth days) solar powered systems with the requisite energy storage in the form of regenerative fuel cells or batteries becomes prohibitively heavy at high power levels ({approximately} 100 kWe). At these high power levels nuclear power systems become an enabling technology for variety of missions. One way of producing power on the lunar surface is with an SP-100 class reactor coupled with Stirling power converters. In this study, analysis and characterization of the SP-100 class reactor coupled with Free Piston Stirling Power Conversion (FPSPC) system will be performed. Comparison of results with previous studies of other systems, particularly Brayton and Thermionic, are made.

Schmitz, P.D. [Sverdrup Technology, Inc., Brook Park, OH (United States). Lewis Research Center Group; Mason, L.S. [National Aeronautics and Space Administration, Cleveland, OH (United States). Lewis Research Center

1994-09-01T23:59:59.000Z

184

High power x-ray welding of metal-matrix composites  

DOE Patents [OSTI]

A method for joining metal-matrix composites (MMCs) by using high power x-rays as a volumetric heat source is provided. The method involves directing an x-ray to the weld line between two adjacent MMCs materials to create an irradiated region or melt zone. The x-rays have a power density greater than about 10.sup.4 watts/cm.sup.2 and provide the volumetric heat required to join the MMC materials. Importantly, the reinforcing material of the metal-matrix composites remains uniformly distributed in the melt zone, and the strength of the MMCs are not diminished. In an alternate embodiment, high power x-rays are used to provide the volumetric heat required to weld metal elements, including metal elements comprised of metal alloys. In an alternate embodiment, high power x-rays are used to provide the volumetric heat required to weld metal elements, including metal elements comprised of metal alloys.

Rosenberg, Richard A. (Naperville, IL); Goeppner, George A. (Orland Park, IL); Noonan, John R. (Naperville, IL); Farrell, William J. (Flossmoor, IL); Ma, Qing (Westmont, IL)

1999-01-01T23:59:59.000Z

185

IKNO, a user facility for coherent terahertz and UV synchrotron radiation  

E-Print Network [OSTI]

Sannibale, F. (2005). CERN Courier, Vol. 45, 7, 39-42. Byrd,2004; Byrd et al. , 2005, CERN Courier), a ring-based sourceByrd et al. , 2005, CERN Courier). THz CSR has been also

Sannibale, Fernando

2009-01-01T23:59:59.000Z

186

Analysis of the Hydration Water around Bovine Serum Albumin using Terahertz Coherent Synchrotron Radiation  

E-Print Network [OSTI]

of the whole protein. 19 Neutron scattering experiments have also shown that scattering profiles for aqueous solutions of apolar amino acid analogs differs from bulk water and hydrophilic amino acid analogs.20 Extended frequency range light scattering...

Bye, J. W.; Meliga, S.; Ferachou, D.; Cinque, G.; Zeitler, J. A.; Falconer, R. J.

187

High Power Impulse Magnetron Sputtering deposition of Pt inside fuel cell electrodes  

E-Print Network [OSTI]

1 High Power Impulse Magnetron Sputtering deposition of Pt inside fuel cell electrodes S Cuynet1 as a cathode of a proton exchange membrane fuel cell. An increase of 80 % at 0.65 V of the PEMFC power density) 272001" #12;2 Proton exchange membrane fuel cells (PEMFC) have the potential to provide

Paris-Sud XI, Université de

188

High-Power InP-based Waveguide Photodiodes and Photodiode Arrays Heterogeneously Integrated on SOI  

E-Print Network [OSTI]

High-Power InP-based Waveguide Photodiodes and Photodiode Arrays Heterogeneously Integrated on SOI evanescently-coupled modified uni-traveling carrier photodiodes (MUTC PDs) on silicon-on-insulator (SOI on silicon is a promising approach to realize high-performance photodiodes on a silicon photonics platform

Bowers, John

189

Highly Conductive and Porous Activated Reduced Graphene Oxide Films for High-Power Supercapacitors  

E-Print Network [OSTI]

Highly Conductive and Porous Activated Reduced Graphene Oxide Films for High-Power Supercapacitors for a free-standing carbon film reported to date. A two-electrode supercapacitor using these carbon films. KEYWORDS: Graphene, flexible film, chemical activation, supercapacitors Free-standing thin film materials

190

High power CW dye laser emission around 888 nm M. Leduc and G. Trenec  

E-Print Network [OSTI]

355 High power CW dye laser emission around 888 nm M. Leduc and G. Trenec Laboratoire de report a maximum output power of 1.5 W at 888 nm from a HITC jet stream dye laser pumped by a Kr+ laser above previously reported results. Good stability of the dye solution is observed over months

Paris-Sud XI, Université de

191

Diagnostic Characterization of High-Power Lithium-Ion Batteries For Use in Hybrid Electric Vehicles  

E-Print Network [OSTI]

Diagnostic Characterization of High-Power Lithium-Ion Batteries For Use in Hybrid Electric Vehicles and electric vehicles due to their relatively high specific energy and specific power. The Advanced Technology of lithium-ion batteries for hybrid electric vehicle (HEV) applications. The ATD Program is a joint effort

192

Diagnostic Characterization of High Power Lithium-Ion Batteries for Use in Hybrid Electric Vehicles  

E-Print Network [OSTI]

Diagnostic Characterization of High Power Lithium-Ion Batteries for Use in Hybrid Electric Vehicles are a fast-growing technology that is attrac- tive for use in portable electronics and electric vehicles due electric vehicle HEV applications.c A baseline cell chemistry was identified as a carbon anode negative

193

Mats Lindroos, Cristina Oyon and Stevey OECD "A High Power Spallation Source in each Global Region"  

E-Print Network [OSTI]

ESS Mats Lindroos, Cristina Oyon and Stevey Peggs #12;ESS 2 #12;OECD "A High Power Spallation Source in each Global Region" SNS Oak Ridge J-PARC Tokai ESS in Lund #12;ESS: Site selection process · ESS high up on the ESFRI list Th ti biddi f th it (Bilb L d d· Three consortia bidding for the site

McDonald, Kirk

194

Efficient Transmitters and Receivers for High-Power Wireless Powering Systems  

E-Print Network [OSTI]

and Energy Engineering University of Colorado Boulder ,U.S.A. zoya@colorado.edu Abstract-- The efficiency plane waves carrying ultra-low power levels are scavenged or harvested from known transmitters typically in the UHF or microwave range [7,8]. High power levels are also used in some beaming applications with plane

Popovic, Zoya

195

Cree's High-Power White LED Delivers 121 lm/W  

Broader source: Energy.gov [DOE]

Cree's commercial high-power white LEDs can now deliver 121 lm/W at 35A/cm2 current density. These particular Cree XLamp® XP-G LEDs deliver 267 lumens at a drive current of 700 mA and an operating...

196

ADVANCES IN HIGH-POWER TARGETS* H. KIRK, BNL, UPTON, NY 11973, U.S.A.  

E-Print Network [OSTI]

is the bulk modules, T is the coefficient of thermal expansion, and CV is the thermal heat capacity, one sees and high values of the heat capacity. Additional material property considerations are a high tensile toward solving the technical challenges of developing high-power targets. To date both solid and liquid

McDonald, Kirk

197

Advanced High Energy and High Power Battery Systems for Automotive Applications Khalil Amine  

E-Print Network [OSTI]

-dependent Industry 41% Oil-dependent 17% Oil-dependent 72% 22% 1% 5% U.S. Oil Consumption by End-use Sector 199.30am Advanced High Energy and High Power Battery Systems for Automotive Applications Khalil Amine Argonne National Laboratory Abstract To meet the high-energy requirem ent that can enab le the 40-miles

Levi, Anthony F. J.

198

LAL/RT 04-03 THE TESLA HIGH POWER COUPLER PROGRAM AT ORSAY  

E-Print Network [OSTI]

LAL/RT 04-03 April 2004 1 THE TESLA HIGH POWER COUPLER PROGRAM AT ORSAY T. Garvey, H. Borie, L, Université de Paris-Sud, B.P. 34, 91898 Orsay, France Abstract Within the general TESLA collaboration-Orsay are centred on the development of RF input couplers for the cavities of the TESLA linear collider study

Boyer, Edmond

199

High-power parametric conversion from near-infrared to short-wave infrared  

E-Print Network [OSTI]

High-power parametric conversion from near-infrared to short-wave infrared Adrien Billat,1,* Steevy.billat@epfl.ch Abstract: We report the design of an all-fiber continuous wave Short-Wave Infrared source capable to output.4370) Nonlinear optics, fibers; (140.3070) Infrared and far-infrared lasers. References and links 1. M. N

Dalang, Robert C.

200

Frontier estimation via kernel regression on high power-transformed data  

E-Print Network [OSTI]

Frontier estimation via kernel regression on high power-transformed data S´ephane Girard(1 Abstract We present a new method for estimating the frontier of a multidimensional sample. The estimator is illustrated on some finite sample situations. Keywords: kernel estimator, power-transform, frontier estimation

Paris-Sud XI, Université de

Note: This page contains sample records for the topic "high-power coherent terahertz" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

Generation of Alfven waves by high power pulse at the electron plasma frequency  

E-Print Network [OSTI]

Generation of Alfve´n waves by high power pulse at the electron plasma frequency B. Van CompernolleG, Helium) capable of supporting Alfve´n waves has been studied. The interaction leads to the generation locations. Citation: Van Compernolle, B., W. Gekelman, P. Pribyl, and T. A. Carter (2005), Generation

California at Los Angles, University of

202

SAR image effects on coherence and coherence estimation.  

SciTech Connect (OSTI)

Radar coherence is an important concept for imaging radar systems such as synthetic aperture radar (SAR). This document quantifies some of the effects in SAR which modify the coherence. Although these effects can disrupt the coherence within a single SAR image, this report will focus on the coherence between separate images, such as for coherent change detection (CCD) processing. There have been other presentations on aspects of this material in the past. The intent of this report is to bring various issues that affect the coherence together in a single report to support radar engineers in making decisions about these matters.

Bickel, Douglas Lloyd

2014-01-01T23:59:59.000Z

203

Tailoring the slow light behavior in terahertz metasurfaces  

E-Print Network [OSTI]

We experimentally study the effect of near field coupling on the transmission of light in terahertz metasurfaces, possessing slightly distinctive SRR resonances. Our results show that the interplay between the strengths of electric and magnetic dipoles, modulates the amplitude of resulting electromagnetically induced transmission, probed under different types of asymmetries in the coupled system. We employ a two-particle model to theoretically study the influence of the near field coupling between bright and quasi-dark modes on the transmission properties of the coupled system and we find an excellent agreement with our observed results. Adding to the enhanced transmission characteristics, our results provide a deeper insight into the metamaterial analogues of atomic electromagnetically induced transparency and offer an approach to engineer slow light devices, broadband filters and attenuators at terahertz frequencies.

Manjappa, Manukumara; Cong, Longqing; Bettiol, Andrew A; Zhang, Weili; Singh, Ranjan

2015-01-01T23:59:59.000Z

204

Sensitive room-temperature terahertz detection via the photothermoelectric effect in graphene  

E-Print Network [OSTI]

Sensitive room-temperature terahertz detection via the photothermoelectric effect in graphene . The hot-electron photothermoelectric effect in graphene is a prom- ising detection mechanism; photoexcited, we demonstrate a graphene thermoelectric terahertz photodetector with sensi- tivity exceeding 10 V W

Murphy, Thomas E.

205

POLARIZATION DEPENDENT TERAHERTZ TIME-DOMAIN SPECTROSCOPY MEASUREMENTS ON ALIGNED CARBON NANOTUBE FILMS AND FIBERS  

E-Print Network [OSTI]

Dependent Terahertz Time-Domain Spectroscopy Measurements On Aligned Carbon Nanotube Films And Fibers are not well defined ! Carbon nanotube (CNT) fiber properties strongly determined by overall alignment of itsPOLARIZATION DEPENDENT TERAHERTZ TIME-DOMAIN SPECTROSCOPY MEASUREMENTS ON ALIGNED CARBON NANOTUBE

Mellor-Crummey, John

206

Plasmonic Nature of the Terahertz Conductivity Peak in Single-Wall Carbon Nanotubes  

E-Print Network [OSTI]

Plasmonic Nature of the Terahertz Conductivity Peak in Single-Wall Carbon Nanotubes Qi Zhang, Erik resonance is expected to occur in metallic and doped semiconducting carbon nanotubes in the terahertz conductivity peak commonly observed for carbon nanotube ensembles remains controversial. Here we present

Kono, Junichiro

207

A Study Of Semiconductor Quantum Dots In The Application To Terahertz Sensors  

E-Print Network [OSTI]

A Study Of Semiconductor Quantum Dots In The Application To Terahertz Sensors Raymond Davis M and referenced as part of background information used in this project. Raymond Davis October 1, 2011 ii #12 sensors. For detection of terahertz radia- tion we probe charge excitations of QDs caused

Sheldon, Nathan D.

208

Scattering of terahertz radiation on a graphene-based nano-antenna  

E-Print Network [OSTI]

Scattering of terahertz radiation on a graphene-based nano-antenna Ignacio Llatser, , Christian. Scattering of the terahertz radiation on a graphene-based nano-antenna is considered. Different electromagnetic models of graphene are discussed and applied to calculate extinction, scattering and absorption

Politècnica de Catalunya, Universitat

209

Strong Enhancement of Terahertz Radiation from Laser Filaments in Air by a Static Electric Field  

E-Print Network [OSTI]

1 Strong Enhancement of Terahertz Radiation from Laser Filaments in Air by a Static Electric Field radiation from the laser filament is highly sensitive to the presence of a transverse electric field. We observe a three order of magnitude enhancement of the terahertz (THz) energy radiated by a femtosecond

Paris-Sud XI, Université de

210

IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS 1 Modeling of Terahertz Heating Effects in  

E-Print Network [OSTI]

experiments involving biological tissues. Index Terms--Far infrared, Terahertz Heating, Breast and BrainIEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS 1 Modeling of Terahertz Heating Effects in real tissues causes heating as with any other electromagnetic radiation propagation. A finite element

Ganesan, Sashikumaar

211

An exploration of the utilities of terahertz waves for the NDE of composites  

SciTech Connect (OSTI)

We report an investigation of terahertz waves for the nondestructive evaluation of composite materials and structures. The modalities of the terahertz radiation used were time domain spectroscopy (TDS) and continuous wave (CW). The composite materials and structures investigated include both non-conducting polymeric composites and carbon fiber composites. Terahertz signals in the TDS mode resembles that of ultrasound; however, unlike ultrasound, a terahertz pulse can detect a crack hidden behind a larger crack. This was demonstrated in thick GFRP laminates containing double saw slots. In carbon composites the penetration of terahertz waves is quite limited and the detection of flaws is strongly affected by the angle between the electric field vector of the terahertz waves and the intervening fiber directions. The structures tested in this study include both solid laminates and honeycomb sandwiches. The defects and anomalies investigated by terahertz waves were foreign material inclusions, simulated disbond and delamination, mechanical impact damage, heat damage, and water or hydraulic fluid ingression. The effectiveness and limitations of terahertz radiation for the NDE of composites are discussed.

Hsu, David K.; Im, Kwang-Hee; Chiou, Chien-Ping; Barnard, Daniel J. [Center for Nondestructive Evaluation, Iowa State University, Ames, Iowa 50011 (United States)

2011-06-23T23:59:59.000Z

212

PHYSICAL REVIEW B 84, 115421 (2011) Efficient terahertz emission from InAs nanowires  

E-Print Network [OSTI]

PHYSICAL REVIEW B 84, 115421 (2011) Efficient terahertz emission from InAs nanowires Denis V, University of New Mexico, Albuquerque, NM 87131, USA 2 Sandia National Laboratories, Albuquerque, NM 87185 measurements of electronic transport on individual nanowires, ultrafast terahertz spectroscopy, and theoretical

Sheik-Bahae, Mansoor

213

Tunable and collimated terahertz radiation generation by femtosecond laser pulses  

SciTech Connect (OSTI)

A mechanism is proposed for the generation of tunable terahertz (THz) radiation under the application of two femtosecond laser pulses and an external magnetic field, where quick tunnel ionization is achieved that leads to higher plasma density evolution and large residual current for the efficient THz radiation generation. With the optimization of magnetic field, phase difference, and amplitudes of lasers' fields, a THz source can be obtained with tunable frequency and power along with a control on the direction of radiation emission.

Malik, Hitendra K.; Malik, Anil K.

2011-12-19T23:59:59.000Z

214

Polymer microstructured optical fibers for terahertz wave guiding  

E-Print Network [OSTI]

. Valdes, F. A. Vallejo, L. M. Hayden, B. Polishak, X.-H. Zhou, J. Luo, A. K. Jen, J. C. Williams, and R. J.6495) Spectroscopy, terahertz. References and links 1. G. Imeshev, M. E. Fermann, K. L. Vodopyanov, M. M. Fejer, X-patterned GaAs pumped by a fiber laser," Opt. Express 14(10), 4439­4444 (2006). 2. M. Tang, H. Minamide, Y

Skorobogatiy, Maksim

215

The development of low cost LiFePO4-based high power lithium-ion batteries  

E-Print Network [OSTI]

study of rechargeable lithium batteries for application inin consumer-size lithium batteries, such as the synthetic4 -BASED HIGH POWER LITHIUM-ION BATTERIES Joongpyo Shim,

Shim, Joongpyo; Sierra, Azucena; Striebel, Kathryn A.

2003-01-01T23:59:59.000Z

216

Materials data requirements for high power target design E. Noah, 4th HPTW, Malm, SE, 2-6 May 2011  

E-Print Network [OSTI]

: Safety Reliability of components > Motivation for codes and standards: Contractual: client/contractor/supplier. construction qualification. examinations. #12;Materials data requirements for high power target design E

McDonald, Kirk

217

Bidirectional coherent classical communication  

E-Print Network [OSTI]

A unitary interaction coupling two parties enables quantum communication in both the forward and backward directions. Each communication capacity can be thought of as a tradeoff between the achievable rates of specific types of forward and backward communication. Our first result shows that for any bipartite unitary gate, coherent classical communication is no more difficult than classical communication -- they have the same achievable rate regions. Previously this result was known only for the unidirectional capacities (i.e., the boundaries of the tradeoff). We then relate the tradeoff curve for two-way coherent communication to the tradeoff for two-way quantum communication and the tradeoff for coherent communiation in one direction and quantum communication in the other.

Aram W. Harrow; Debbie W. Leung

2005-05-12T23:59:59.000Z

218

Coherent soliton communication lines  

SciTech Connect (OSTI)

The data transmission in coherent fiber-optical communication lines using solitons with a variable phase is studied. It is shown that nonlinear coherent structures (solitons) can be applied for effective signal transmission over a long distance using amplitude and optical-phase keying of information. The optimum ratio of the pulse width to the bit slot at which the spectral efficiency (transmitted bits per second and hertz) is maximal is determined. It is shown that soliton fiber-optical communication lines can ensure data transmission at a higher spectral efficiency as compared to traditional communication lines and at a high signal-to-noise ratio.

Yushko, O. V., E-mail: olesya.yushko@gmail.com; Redyuk, A. A.; Fedoruk, M. P.; Turitsyn, S. K. [Novosibirsk State University (Russian Federation)

2014-11-15T23:59:59.000Z

219

Design of a High Power Continuous Source of Broadband Down-Converted Light  

E-Print Network [OSTI]

We present the design and experimental proof of principle of a low threshold optical parametric oscillator (OPO) that continuously oscillates over a large bandwidth allowed by phase matching. The large oscillation bandwidth is achieved with a selective two-photon loss that suppresses the inherent mode competition, which tends to narrow the bandwidth in conventional OPOs. Our design performs pairwise mode-locking of many frequency pairs, in direct equivalence to passive mode-locking of ultrashort pulsed lasers. The ability to obtain high powers of continuous \\textit{and} broadband down-converted light enables the optimal exploitation of the correlations within the down-converted spectrum, thereby strongly affecting two-photon interactions even at classically high power levels, and opening new venues for applications such as two-photon spectroscopy and microscopy and optical spread spectrum communication.

Avi Pe'er; Yaron Silberberg; Barak Dayan; Asher A. Friesem

2006-08-29T23:59:59.000Z

220

Collective Thomson scattering of a high power electron cyclotron resonance heating beam in LHD (invited)  

SciTech Connect (OSTI)

Collective Thomson scattering (CTS) system has been constructed at LHD making use of the high power electron cyclotron resonance heating (ECRH) system in Large Helical Device (LHD). The necessary features for CTS, high power probing beams and receiving beams, both with well defined Gaussian profile and with the fine controllability, are endowed in the ECRH system. The 32 channel radiometer with sharp notch filter at the front end is attached to the ECRH system transmission line as a CTS receiver. The validation of the CTS signal is performed by scanning the scattering volume. A new method to separate the CTS signal from background electron cyclotron emission is developed and applied to derive the bulk and high energy ion components for several combinations of neutral beam heated plasmas.

Kubo, S.; Nishiura, M.; Tanaka, K.; Shimozuma, T.; Yoshimura, Y.; Igami, H.; Takahash, H.; Mutoh, T. [National Institute for Fusion Science, 322-6 Oroshi-cho, Toki, 509-5292 Gifu (Japan); Tamura, N. [Department of Energy Science and Technology, Nagoya University, Nagoya 464-8463 (Japan); Tatematsu, Y.; Saito, T. [Research Center for Development of FIR Region, University of Fukui, Fukui 910-8507 (Japan); Notake, T. [Tera-Photonics Lab., RIKEN, Sendai 980-0845 (Japan); Korsholm, S. B.; Meo, F.; Nielsen, S. K.; Salewski, M.; Stejner, M. [Association EURATOM-Risoe DTU, P.O. Box 49, DK-4000 Roskilde (Denmark)

2010-10-15T23:59:59.000Z

Note: This page contains sample records for the topic "high-power coherent terahertz" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

Thermal And Mechanical Analysis of High-power Light-emitting Diodes with Ceramic Packages  

E-Print Network [OSTI]

In this paper we present the thermal and mechanical analysis of high-power light-emitting diodes (LEDs) with ceramic packages. Transient thermal measurements and thermo-mechanical simulation were performed to study the thermal and mechanical characteristics of ceramic packages. Thermal resistance from the junction to the ambient was decreased from 76.1 oC/W to 45.3 oC/W by replacing plastic mould to ceramic mould for LED packages. Higher level of thermo-mechanical stresses in the chip were found for LEDs with ceramic packages despite of less mismatching coefficients of thermal expansion comparing with plastic packages. The results suggest that the thermal performance of LEDs can be improved by using ceramic packages, but the mounting process of the high power LEDs with ceramic packages is critically important and should be in charge of delaminating interface layers in the packages.

J. Hu; L. Yang; M. -W. Shin

2008-01-07T23:59:59.000Z

222

TRANSFORMATIONAL LEADERSHIP AND ALTRUISM: ROLE OF POWER DISTANCE IN A HIGH POWER DISTANCE CULTURE  

E-Print Network [OSTI]

Using a sample of 105 manager-subordinate dyads from a high power distance culture, the effects of power distance and transformational leadership on follower altruism were studied. Findings show a significant positive relationship between power distance and transformational leadership and between transformational leadership and follower altruism. The dimensions on which cultures differ have been identified earlier (Hofstede, 1980). The objective of this study is to look at the effect of a dimension on other variables, in a culture that is high on that dimension. Our contention is that in cultures that score high on the power distance dimension of Hofstede (1980) model, if managers maintain a high power distance between themselves and their followers, their transformational leadership would be enhanced, and transformational leadership in turn will enhance altruistic behavior of followers. Merely knowing the dimensions on which cultures differ is not enough. That knowledge has to be used to predict how an alignment with that dimension would affect other variables.

Ankush Punj; Venkat R. Krishnan

223

Coherent Radiation in an Undulator  

E-Print Network [OSTI]

solving the particle-radiation system in a self-consistentto clarify the coherent radiation mechanism. References 1.the Proceedings Coherent Radiation in an Undulator Y,H. Chin

Chin, Y.H.

2011-01-01T23:59:59.000Z

224

AlGaAs/GaAs photovoltaic converters for high power narrowband radiation  

SciTech Connect (OSTI)

AlGaAs/GaAs-based laser power PV converters intended for operation with high-power (up to 100 W/cm{sup 2}) radiation were fabricated by LPE and MOCVD techniques. Monochromatic (? = 809 nm) conversion efficiency up to 60% was measured at cells with back surface field and low (x = 0.2) Al concentration 'window'. Modules with a voltage of 4 V and the efficiency of 56% were designed and fabricated.

Khvostikov, Vladimir; Kalyuzhnyy, Nikolay; Mintairov, Sergey; Potapovich, Nataliia; Shvarts, Maxim; Sorokina, Svetlana; Andreev, Viacheslav [Ioffe Physical-Technical Institute, 26 Polytechnicheskaya, St. Petersburg, 194021 (Russian Federation); Luque, Antonio [Ioffe Physical-Technical Institute, 26 Polytechnicheskaya, St. Petersburg, 194021, Russia and Instituto de Energia Solar, Universidad Politecnica de Madrid, Madrid (Spain)

2014-09-26T23:59:59.000Z

225

High Power Testing of RF Cavities for the PEP II B Factory  

SciTech Connect (OSTI)

We describe the process of conditioning and high-power testing of RF cavities for PEP-II. Procedures for vacuum assembly, bakeout and automated processing are described. Interlocks and safety precautions for protection of equipment and personnel are discussed and performance data of tested cavity assemblies are reported. Performance of ancillary components such as windows, couplers and tuners is also discussed. Comments are included on handling, alignment, installation and commissioning issues where appropriate.

Rimmer, R.A.; /LBL, Berkeley; Allen, M.; Fant, K.; Hill, A.; Hoyt, M.; Judkins, J.; Neubauer, Mark Stephen; Schwarz, H.; /SLAC

2011-09-01T23:59:59.000Z

226

Investigation of the delay time distribution of high power microwave surface flashover  

SciTech Connect (OSTI)

Characterizing and modeling the statistics associated with the initiation of gas breakdown has proven to be difficult due to a variety of rather unexplored phenomena involved. Experimental conditions for high power microwave window breakdown for pressures on the order of 100 to several 100 torr are complex: there are little to no naturally occurring free electrons in the breakdown region. The initial electron generation rate, from an external source, for example, is time dependent and so is the charge carrier amplification in the increasing radio frequency (RF) field amplitude with a rise time of 50 ns, which can be on the same order as the breakdown delay time. The probability of reaching a critical electron density within a given time period is composed of the statistical waiting time for the appearance of initiating electrons in the high-field region and the build-up of an avalanche with an inherent statistical distribution of the electron number. High power microwave breakdown and its delay time is of critical importance, since it limits the transmission through necessary windows, especially for high power, high altitude, low pressure applications. The delay time distribution of pulsed high power microwave surface flashover has been examined for nitrogen and argon as test gases for pressures ranging from 60 to 400 torr, with and without external UV illumination. A model has been developed for predicting the discharge delay time for these conditions. The results provide indications that field induced electron generation, other than standard field emission, plays a dominant role, which might be valid for other gas discharge types as well.

Foster, J.; Krompholz, H.; Neuber, A. [Department of Electrical and Computer Engineering, Center for Pulsed Power and Power Electronics, Texas Tech University, Lubbock, Texas 79409-3102 (United States)

2011-01-15T23:59:59.000Z

227

Photoionization of optically trapped ultracold atoms with a high-power light-emitting diode  

SciTech Connect (OSTI)

Photoionization of laser-cooled atoms using short pulses of a high-power light-emitting diode (LED) is demonstrated. Light pulses as short as 30 ns have been realized with the simple LED driver circuit. We measure the ionization cross section of {sup 85}Rb atoms in the first excited state, and show how this technique can be used for calibrating efficiencies of ion detector assemblies.

Goetz, Simone; Hoeltkemeier, Bastian; Amthor, Thomas; Weidemueller, Matthias [Physikalisches Institut, Universitaet Heidelberg, Im Neuenheimer Feld 226, 69120 Heidelberg (Germany)

2013-04-15T23:59:59.000Z

228

Quantum Coherence Engines  

E-Print Network [OSTI]

In a report published in Science, Scully et al propose to generate "phaseonium", and "extract work from a single heat bath via vanishing coherence" [1]. On the basis of the laws of physics, such a proposal is futile for at least two reasons.

Elias P. Gyftopoulos

2007-06-20T23:59:59.000Z

229

High-Power Detectors Newport Corporation warrants this product to be free from defects In material and  

E-Print Network [OSTI]

High-Power Detectors #12;Warranty Newport Corporation warrants this product to be free from defects.3 Unpacking and Inspection 2 Section 2 - Detector Operation 2.1 Introduction 3 2.2 Power Signal Behavior 3 2 Reflections 7 2.7 Spectral Response 8 2.8 Care for High-Power Detectors 9 2.9 Detector Recalibration 9 Section

Kleinfeld, David

230

Coherent hybrid electromagnetic field imaging  

DOE Patents [OSTI]

An apparatus and corresponding method for coherent hybrid electromagnetic field imaging of a target, where an energy source is used to generate a propagating electromagnetic beam, an electromagnetic beam splitting means to split the beam into two or more coherently matched beams of about equal amplitude, and where the spatial and temporal self-coherence between each two or more coherently matched beams is preserved. Two or more differential modulation means are employed to modulate each two or more coherently matched beams with a time-varying polarization, frequency, phase, and amplitude signal. An electromagnetic beam combining means is used to coherently combine said two or more coherently matched beams into a coherent electromagnetic beam. One or more electromagnetic beam controlling means are used for collimating, guiding, or focusing the coherent electromagnetic beam. One or more apertures are used for transmitting and receiving the coherent electromagnetic beam to and from the target. A receiver is used that is capable of square-law detection of the coherent electromagnetic beam. A waveform generator is used that is capable of generation and control of time-varying polarization, frequency, phase, or amplitude modulation waveforms and sequences. A means of synchronizing time varying waveform is used between the energy source and the receiver. Finally, a means of displaying the images created by the interaction of the coherent electromagnetic beam with target is employed.

Cooke, Bradly J. (Jemez Springs, NM); Guenther, David C. (Los Alamos, NM)

2008-08-26T23:59:59.000Z

231

Dual-frequency terahertz emission from splitting filaments induced by lens tilting in air  

SciTech Connect (OSTI)

Dual-frequency terahertz radiation from air-plasma filaments produced with two-color lasers in air has been demonstrated experimentally. When a focusing lens is tilted for a few degrees, it is shown that the laser filament evolves from a single one to two sub-filaments. Two independent terahertz sources emitted from the sub-filaments with different frequencies and polarizations are identified, where the frequency of terahertz waves from the trailing sub-filament is higher than that from the leading sub-filament.

Zhang, Zhelin; Chen, Yanping, E-mail: yanping.chen@sjtu.edu.cn; Yang, Liu; Yuan, Xiaohui; Liu, Feng; Chen, Min; Xu, Jianqiu; Zhang, Jie [Key Laboratory for Laser Plasmas (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China); Sheng, Zhengming [Key Laboratory for Laser Plasmas (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China); Department of Physics, SUPA, University of Strathclyde, Glasgow G4 0NG (United Kingdom)

2014-09-08T23:59:59.000Z

232

Stimulated Terahertz Emission from Intra-Excitonic Transitions inCu2O  

SciTech Connect (OSTI)

We report the first observation of stimulated emission of terahertz radiation from internal transitions of excitons. The far-infrared electromagnetic response of Cu{sub 2}O is monitored via broadband terahertz pulses after ultrafast resonant excitation of three-dimensional 3p excitons. Stimulated emission from the 3p to the energetically lower 2s bound level occurs at a photon energy of 6.6 meV, with a cross section of {approx} 10{sup 14} cm{sup 2}. Simultaneous excitation of both exciton levels, in turn, drives quantum beats which lead to efficient terahertz emission sharply peaked at the difference frequency.

Huber, Rupert; Schmid, Ben A.; Shen, Y. Ron; Chemla, Daniel S.; Kaindl, Robert A.

2005-06-16T23:59:59.000Z

233

Theoretical foundations of detection of terahertz radiation in laser-plasma interactions  

SciTech Connect (OSTI)

A theory is developed enabling one to calculate the temporal profile and spectrum of a terahertz wave packet from the energy of the second harmonic of optical radiation generated during the nonlinear interaction between terahertz and circularly polarized laser pulses in the skin layer of an overdense plasma. It is shown that the spectral and temporal characteristics of the envelope of the second harmonic of optical radiation coincide with those of the terahertz pulse only at small durations of the detecting laser radiation. For long laser pulses, the temporal profile and spectrum of the second harmonic are mainly determined by the characteristics of optical radiation at the carrier frequency.

Frolov, A. A., E-mail: frolov@ihed.ras.ru [Russian Academy of Sciences, Joint Institute for High Temperatures (Russian Federation)

2013-02-15T23:59:59.000Z

234

Graphene-based terahertz photodetector by noise thermometry technique  

SciTech Connect (OSTI)

We report the characteristics of graphene-based terahertz (THz) photodetector based on noise thermometry technique by measuring its noise power at frequency from 4 to 6 GHz. Hot electron system in graphene microbridge is generated after THz photon pumping and creates extra noise power. The equivalent noise temperature and electron temperature increase rapidly in low THz pumping regime and saturate gradually in high THz power regime which is attributed to a faster energy relaxation process involved by stronger electron-phonon interaction. Based on this detector, a conversion efficiency around 0.15 from THz power to noise power in 4–6?GHz span has been achieved.

Wang, Ming-Jye, E-mail: mingjye@asiss.sinica.edu.tw [Institute of Astronomy and Astrophysics, Academia Sinica, Taipei 10617, Taiwan (China); Institute of Physics, Academia Sinica, Taipei 11529, Taiwan (China); Wang, Ji-Wun [Institute of Astronomy and Astrophysics, Academia Sinica, Taipei 10617, Taiwan (China); Department of Physics, National Tsing-Hua University, Hsinchu 30013, Taiwan (China); Wang, Chun-Lun; Chiang, Yen-Yu; Chang, Hsian-Hong [Institute of Astronomy and Astrophysics, Academia Sinica, Taipei 10617, Taiwan (China)

2014-01-20T23:59:59.000Z

235

Investigating the effective range of vacuum ultraviolet-mediated breakdown in high-power microwave metamaterials  

SciTech Connect (OSTI)

Metamaterials and periodic structures operating under high-power excitations are susceptible to breakdown. It was recently demonstrated that a localized breakdown created in a given region of a periodic structure can facilitate breakdown in other regions of the structure where the intensity of the incident electromagnetic fields may not be high enough to cause breakdown under normal circumstances. It was also demonstrated that this phenomenon is due to the generation of vacuum ultraviolet radiation at the location of the initial discharge, which propagates to the neighboring regions (e.g., other unit cells in a periodic structure) and facilitates the generation of a discharge at a lower incident power level. In this paper, we present the results of an experimental study conducted to determine the effective range of this physical phenomenon for periodic structures that operate in air and in pure nitrogen gas at atmospheric pressure levels. It is demonstrated that when breakdown is induced in a periodic structure using a high-power pulse with a frequency of 9.382 GHz, duration of 0.8??s, and peak power level of 25?kW, this phenomenon is highly likely to happen in radii of approximately 16–17?mm from the location of the initial discharge under these test conditions. The results of this study are significant in designing metamaterials and periodic structures for high-power microwave applications as they suggest that a localized discharge created in such a periodic structure with a periodicity less than 16–17?mm can spread over a large surface and result in a distributed discharge.

Liu, Chien-Hao, E-mail: cliu82@wisc.edu; Neher, Joel D., E-mail: jdneher@wisc.edu; Booske, John H., E-mail: booske@engr.wisc.edu; Behdad, Nader, E-mail: behdad@wisc.edu [Department of Electrical and Computer Engineering, University of Wisconsin-Madison, 1415 Engineering Drive, Madison, Wisconsin 53706 (United States)

2014-10-14T23:59:59.000Z

236

Interaction of a High-Power Laser Beam with Metal Sheets  

SciTech Connect (OSTI)

Experiments with a high-power laser beam directed onto thin aluminum sheets, with a large spot size, demonstrate that airflow produces a strong enhancement of the interaction. The enhancement is explained in terms of aerodynamic effects. As laser heating softens the material, the airflow-induced pressure difference between front and rear faces causes the metal to bulge into the beam. The resulting shear stresses rupture the material and remove it at temperatures well below the melting point. The material heating is shown to conform to an elementary model. We present an analytic model of elastic bulging. Scaling with respect to spot size, wind speed, and material parameters is determined.

Boley, C D; Cutter, K P; Fochs, S N; Pax, P H; Rotter, M D; Rubenchik, A M; Yamamoto, R M

2009-06-24T23:59:59.000Z

237

High Power, High Voltage FETs in Linear Applications: A User's Perspective  

SciTech Connect (OSTI)

The specifications of the current crop of highpower, high-voltage field-effect transistors (FETs) can lure a designer into employing them in high-voltage DC equipment. Devices with extremely low on-resistance and very high power ratings are available from several manufacturers. However, our experience shows that high-voltage, linear operation of these devices at near-continuous duty can present difficult reliability challenges at stress levels well-below their published specifications. This paper chronicles the design evolution of a 600 volt, 8 ampere shunt regulator for use with megawatt-class radio transmitters, and presents a final design that has met its reliability criteria.

N. Greenough, E. Fredd, S. DePasquale

2009-09-21T23:59:59.000Z

238

Note: Efficient generation of optical sidebands at GHz with a high-power tapered amplifier  

SciTech Connect (OSTI)

Two methods using a laser-diode tapered amplifier to produce high-power, high-efficiency optical frequency sidebands over a wide tunable frequency range are studied and compared. For a total output of 500 mW at 811 nm, 20% of the power can be placed in each of the first-order sidebands. Functionality and characterization are presented within the sideband frequency region of 0.8–2.3 GHz, and it is shown that both methods can be applied beyond this frequency range. These methods provide a versatile and effective tool for atomic physics experiments.

Zappala, J. C.; Lu, Z.-T. [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States) [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Department of Physics and Enrico Fermi Institute, University of Chicago, Chicago, Illinois 60637 (United States); Bailey, K.; O’Connor, T. P.; Jiang, W., E-mail: wjiang@phy.anl.gov [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States)

2014-04-15T23:59:59.000Z

239

Improved Structure and Fabrication of Large, High-Power KHPS Rotors - Final Scientific/Technical Report  

SciTech Connect (OSTI)

Verdant Power, Inc, working in partnership with the National Renewable Energy Laboratory (NREL), Sandia National Laboratories (SNL), and the University of Minnesota St. Anthony Falls Laboratory (SAFL), among other partners, used evolving Computational Fluid Dynamics (CFD) and Finite Element Analysis (FEA) models and techniques to improve the structure and fabrication of large, high-power composite Kinetic Hydropower System (KHPS) rotor blades. The objectives of the project were to: design; analyze; develop for manufacture and fabricate; and thoroughly test, in the lab and at full scale in the water, the improved KHPS rotor blade.

Corren, Dean [Verdant Power, Inc.; Colby, Jonathan [Verdant Power, Inc.; Adonizio, Mary Ann [Verdant Power, Inc.

2013-01-29T23:59:59.000Z

240

New High Power Li2MTi6O14Anode Material | Department of Energy  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

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Note: This page contains sample records for the topic "high-power coherent terahertz" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

Photoconductivity of graphene devices induced by terahertz radiation at various photon energies  

SciTech Connect (OSTI)

The influence of a magnetic field on Landau levels (LLs) in graphene-based devices is described via the magneto-optical response induced by terahertz (THz) radiation. For single-layer graphene, the resonance energies of the transitions between the on Landau levels (LLs) such as L{sub 1}, L{sub 2} and L{sub 3} fit quite well to the terahertz spectral range at low magnetic fields. Also, the calculations for the terahertz photoresponse (photoconductivity) in the presence of low magnetic fields, the reported calculations for the scattering rate of LLs, recent and our experimental results of photoresponse measurements yield that single-layer graphene is suitable for the detection of terahertz radiation.

Salman, M.; Nachtwei, G. [NTH School for Contacts in Nanosystems, Germany and Institut fuer Angewandte Physik, Technische Universitaet Braunschweig, D-38106 Braunschweig (Germany); Gouider, F.; Göthlich, M. [Institut fuer Angewandte Physik, Technische Universitaet Braunschweig, D-38106 Braunschweig (Germany); Friedemann, M.; Ahlers, F. J. [Physikalisch Technische Bundesanstalt (PTB), Bundesallee 100, D-38116 Braunschweig (Germany); Schmidt, H.; Haug, R. J. [NTH School for Contacts in Nanosystems, Germany and Institut fuer Festkoerperphysik, Universitaet Hannover, D-30167 Hannover (Germany)

2013-12-04T23:59:59.000Z

242

A high carrier injection terahertz quantum cascade laser based on indirectly pumped scheme  

E-Print Network [OSTI]

A Terahertz quantum cascade laser with a rather high injection coupling strength based on an indirectly pumped scheme is designed and experimentally implemented. To effectively suppress leakage current, the chosen quantum ...

Razavipour, S. G.

243

An indirectly pumped terahertz quantum cascade laser with low injection coupling strength operating above 150?K  

E-Print Network [OSTI]

We designed and demonstrated a terahertz quantum cascade laser based on indirect pump injection to the upper lasing state and phonon scattering extraction from the lower lasing state. By employing a rate equation formalism ...

Razavipour, S. G.

244

Nonlinear terahertz spectroscopy of electronic and vibrational responses in condensed matter systems  

E-Print Network [OSTI]

In this work, I describe experiments utilizing high-field terahertz (THz) pulses to initiate nonlinear responses in several classes of materials. We have developed several methods for interrogating the nonlinear THz response ...

Hwang, Harold Young

2012-01-01T23:59:59.000Z

245

FERROELECTRIC SWITCH FOR A HIGH-POWER Ka-BAND ACTIVE PULSE COMPRESSOR  

SciTech Connect (OSTI)

Results are presented for design of a high-power microwave switch for operation at 34.3 GHz, intended for use in an active RF pulse compressor. The active element in the switch is a ring of ferroelectric material, whose dielectric constant can be rapidly changed by application of a high-voltage pulse. As envisioned, two of these switches would be built into a pair of delay lines, as in SLED-II at SLAC, so as to allow 30-MW ?s-length Ka-band pulses to be compressed in time by a factor-of-9 and multiplied in amplitude to generate 200 MW peak power pulses. Such high-power pulses could be used for testing and evaluation of high-gradient mm-wave accelerator structures, for example. Evaluation of the switch design was carried out with an X-band (11.43 GHz) prototype, built to incorporate all the features required for the Ka-band version.

Hirshfield, Jay L. [Omega-P, Inc.] [Omega-P, Inc.

2013-12-18T23:59:59.000Z

246

System efficiency analysis for high power solid state radio frequency transmitter  

SciTech Connect (OSTI)

This paper examines some important relationships, related with the system efficiency, for very high power, radio frequency solid-state transmitter; incorporating multiple solid-state power amplifier modules, power combiners, dividers, couplers, and control/interlock hardware. In particular, the characterization of such transmitters, at the component as well as the system level, is discussed. The analysis for studying the influence of the amplitude and phase imbalance, on useful performance parameters like system efficiency and power distribution is performed. This analysis is based on a scattering parameter model. This model serves as a template for fine-tuning the results, with the help of a system level simulator. For experimental study, this approach is applied to a recently designed modular and scalable solid-state transmitter, operating at the centre frequency of 505.8?MHz and capable of delivering a continuous power of 75 kW. Such first time presented, system level study and experimental characterization for the real time operation will be useful for the high power solid-state amplifier designs, deployed in particle accelerators.

Jain, Akhilesh, E-mail: ajain@rrcat.gov.in; Sharma, D. K.; Gupta, A. K.; Lad, M. R.; Hannurkar, P. R. [RF Systems Division, Raja Ramanna Centre for Advanced Technology, Indore 452013 (India)] [RF Systems Division, Raja Ramanna Centre for Advanced Technology, Indore 452013 (India); Pathak, S. K. [Electromagnetics and Microwave Engineering, Institute for Plasma Research, Gandhinagar 382 428 (India)] [Electromagnetics and Microwave Engineering, Institute for Plasma Research, Gandhinagar 382 428 (India)

2014-02-15T23:59:59.000Z

247

High-power LEDs based on InGaAsP/InP heterostructures  

SciTech Connect (OSTI)

High-power light-emitting diodes (LEDs) with mesa diameters of 100, 200, and 300 ?m are developed on the basis of InGaAsP/InP heterostructures. The mesas are close in shape to a truncated cone with a generatrix inclination angle of ?45° in the vicinity of the active region of the LED, with a ring etched around the mesa serving as a reflector. The emission spectra and directivity patterns of these LEDs are studied in a wide range of current densities and it is shown that radiative recombination is dominant to a current density of ?5000 A/cm{sup 2}, which makes these structures promising for the development of high-power LEDs. An emission power of ?14 mW is obtained in the continuous-wave mode (I = 0.2 A, ? = 1.1 ?m), and that of 77 mW, in the pulsed mode (I = 2 A, ? = 1.1 ?m), which corresponds to external quantum efficiencies of 6.2 and 3.4%, respectively.

Rakovics, V. [Hungarian Academy of Sciences, Institute of Technical Physics and Materials Science, Research Centre for Natural Sciences (Hungary); Imenkov, A. N.; Sherstnev, V. V.; Serebrennikova, O. Yu.; Il’inskaya, N. D.; Yakovlev, Yu. P., E-mail: Yak@iropt1.ioffe.ru [Russian Academy of Sciences, Ioffe Physical-Technical Institute (Russian Federation)

2014-12-15T23:59:59.000Z

248

COLLECTIVE EVIDENCE FOR INVERSE COMPTON EMISSION FROM EXTERNAL PHOTONS IN HIGH-POWER BLAZARS  

SciTech Connect (OSTI)

We present the first collective evidence that Fermi-detected jets of high kinetic power (L{sub kin}) are dominated by inverse Compton emission from upscattered external photons. Using a sample with a broad range in orientation angle, including radio galaxies and blazars, we find that very high power sources (L{sub kin} > 10{sup 45.5} erg s{sup -1}) show a significant increase in the ratio of inverse Compton to synchrotron power (Compton dominance) with decreasing orientation angle, as measured by the radio core dominance and confirmed by the distribution of superluminal speeds. This increase is consistent with beaming expectations for external Compton (EC) emission, but not for synchrotron self-Compton (SSC) emission. For the lowest power jets (L{sub kin} < 10{sup 43.5} erg s{sup -1}), no trend between Compton and radio core dominance is found, consistent with SSC. Importantly, the EC trend is not seen for moderately high power flat spectrum radio quasars with strong external photon fields. Coupled with the evidence that jet power is linked to the jet speed, this finding suggests that external photon fields become the dominant source of seed photons in the jet comoving frame only for the faster and therefore more powerful jets.

Meyer, Eileen T.; Fossati, Giovanni [Department of Physics and Astronomy, Rice University, Houston, TX 77005 (United States); Georganopoulos, Markos [Department of Physics, Joint Center for Astrophysics, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250 (United States); Lister, Matthew L. [Department of Physics, Purdue University, 525 Northwestern Avenue, West Lafayette, IN 47907 (United States)

2012-06-10T23:59:59.000Z

249

Low-spatial coherence electrically-pumped semiconductor laser for speckle-free full-field imaging  

E-Print Network [OSTI]

The spatial coherence of laser sources has limited their application to parallel imaging and projection due to coherent artifacts, such as speckle. In contrast, traditional incoherent light sources, such as thermal sources or light emitting diodes (LEDs), provide relatively low power per independent spatial mode. Here, we present a chip-scale, electrically-pumped semiconductor laser based on a novel design, demonstrating high power per mode with much lower spatial coherence than conventional laser sources. The laser resonator was fabricated with a chaotic, D-shaped cavity optimized to achieve highly multimode lasing. Lasing occurs simultaneously and independently in ~1000 modes, and hence the total emission exhibits very low spatial coherence. Speckle-free full-field imaging is demonstrated using the chaotic cavity laser as the illumination source. The power per mode of the sample illumination is several orders of magnitude higher than that of a LED or thermal light source. Such a compact, low-cost source, wh...

Redding, B; Huang, X; Lee, M L; Stone, A D; Choma, M A; Cao, H

2014-01-01T23:59:59.000Z

250

Electro-optic crystal mosaics for the generation of terahertz radiation  

DOE Patents [OSTI]

Apparatus for the generation of high energy terahertz radiation is presented and comprises laser means effective to produce subpicosecond optical pulses and a mosaic comprising a plurality of planar electro-optic crystals fastened together edge to edge in the form of a grid. The electro-optic crystals are in optical communication with the subpicosecond optical pulses, and behave as a single large electro-optic crystal, producing high energy terahertz radiation by way of optical rectification.

Carrig, Timothy J. (Los Alamos, NM); Taylor, Antoinette J. (Los Alamos, NM); Stewart, Kevin R. (Schenectady, NY)

1996-01-01T23:59:59.000Z

251

Room temperature broadband terahertz gains in graphene heterostructures based on inter-layer radiative transitions  

SciTech Connect (OSTI)

We exploit inter-layer radiative transitions to provide gains to amplify terahertz waves in graphene heterostructures. This is achieved by properly doping graphene sheets and aligning their energy bands so that the processes of stimulated emissions can overwhelm absorptions. We derive an expression for the gain estimation and show the gain is insensitive to temperature variation. Moreover, the gain is broadband and can be strong enough to compensate the free carrier loss, indicating graphene based room temperature terahertz lasers are feasible.

Tang, Linlong [Key Laboratory of High Energy Density Physics and Technology, College of Physics and Technology, Sichuan University, Chengdu, 610064 (China); Chongqing institute of green and intelligent technology, Chinese Academy of Sciences, Chongqing, 401122 (China); Du, Jinglei, E-mail: dujl@scu.edu.cn [Key Laboratory of High Energy Density Physics and Technology, College of Physics and Technology, Sichuan University, Chengdu, 610064 (China); Shi, Haofei, E-mail: shi@cigit.ac.cn; Wei, Dongshan; Du, Chunlei, E-mail: cldu@cigit.ac.cn [Chongqing institute of green and intelligent technology, Chinese Academy of Sciences, Chongqing, 401122 (China)

2014-10-15T23:59:59.000Z

252

Spatial distribution of average charge state and deposition rate in high power impulse magnetron sputtering of copper  

E-Print Network [OSTI]

was ¼ inch (6. 25 mm) thick copper disk. The diameter of thevery high power de nsity. Copper was selected for this studythe high stability of HIPIMS copper discharges ( copper can

Horwat, David

2008-01-01T23:59:59.000Z

253

Technology survey and performance scaling for the design of high power nuclear electric power and propulsion systems  

E-Print Network [OSTI]

High power nuclear electric propulsion systems have the capability to enable many next-generation space exploration applications. To date, use of electric primary propulsion in flight systems has been limited to low-power, ...

White, Daniel B., Jr

2011-01-01T23:59:59.000Z

254

Coherent states on the circle  

E-Print Network [OSTI]

We present a possible construction of coherent states on the unit circle as configuration space. In our approach the phase space is the product Z x S^1. Because of the duality of canonical coordinates and momenta, i.e. the angular variable and the integers, this formulation can also be interpreted as coherent states over an infinite periodic chain. For the construction we use the analogy with our quantization over a finite periodic chain where the phase space was Z_M x Z_M. Properties of the coherent states constructed in this way are studied and the coherent states are shown to satisfy the resolution of unity.

Chadzitaskos, G; Tolar, J

2011-01-01T23:59:59.000Z

255

Linac Coherent Light Source Overview  

ScienceCinema (OSTI)

Take an animated tour of the Linac Coherent Light Source (LCLS). Follow the laser pulse from the injector gun all the way through to the Far Experimental Hall.

None

2013-05-29T23:59:59.000Z

256

Linac Coherent Light Source Overview  

Broader source: Energy.gov [DOE]

Take an animated tour of the Linac Coherent Light Source (LCLS). Follow the laser pulse from the injector gun all the way through to the Far Experimental Hall.

257

Coherent Synchrotron Radiation Analysis  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

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258

Deutsches Terahertz-Zentrum e.V. Anschrift: Philipps-Universitt Marburg, Fachbereich Physik, Hans-Meerwein-Str., MZG-C6, 35032 Marburg  

E-Print Network [OSTI]

Deutsches Terahertz-Zentrum e.V. Anschrift: Philipps-Universität Marburg, Fachbereich Physik, Hans Deutsches Terahertz-Zentrum e.V. Anschrift: Philipps-Universität Marburg, Fachbereich Physik, Hans.terahertzcenter.de E-Mail: info@terahertzcenter.de #12;Deutsches Terahertz-Zentrum e.V. Anschrift: Philipps

Schubart, Christoph

259

A review comparing cathodic arcs and high power impulse magnetron sputtering (HiPIMS)  

SciTech Connect (OSTI)

High power impulse magnetron sputtering (HiPIMS) has been in the center of attention over the last years as it is an emerging physical vapor deposition (PVD) technology that combines advantages of magnetron sputtering with various forms of energetic deposition of films such as ion plating and cathodic arc plasma deposition. It should not come at a surprise that many extension and variations of HiPIMS make use, intentionally or unintentionally, of previously discovered approaches to film processing such as substrate surface preparation by metal ion sputtering and phased biasing for film texture and stress control. Therefore, in this review, an overview is given on some historical developments and features of cathodic arc and HiPIMS plasmas, showing commonalities and differences. To limit the scope, emphasis is put on plasma properties, as opposed to surveying the vast literature on specific film materials and their properties.

Anders, Andre

2014-08-17T23:59:59.000Z

260

High power water load for microwave and millimeter-wave radio frequency sources  

DOE Patents [OSTI]

A high power water load for microwave and millimeter wave radio frequency sources has a front wall including an input port for the application of RF power, a cylindrical dissipation cavity lined with a dissipating material having a thickness which varies with depth, and a rear wall including a rotating reflector for the reflection of wave energy inside the cylindrical cavity. The dissipation cavity includes a water jacket for removal of heat generated by the absorptive material coating the dissipation cavity, and this absorptive material has a thickness which is greater near the front wall than near the rear wall. Waves entering the cavity reflect from the rotating reflector, impinging and reflecting multiple times on the absorptive coating of the dissipation cavity, dissipating equal amounts of power on each internal reflection.

Ives, R. Lawrence (Saratoga, CA); Mizuhara, Yosuke M. (Palo Alto, CA); Schumacher, Richard V. (Sunnyvale, CA); Pendleton, Rand P. (Saratoga, CA)

1999-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "high-power coherent terahertz" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

High-Power Solid-State Lasers from a Laser Glass Perspective  

SciTech Connect (OSTI)

Advances in laser glass compositions and manufacturing have enabled a new class of high-energy/high-power (HEHP), petawatt (PW) and high-average-power (HAP) laser systems that are being used for fusion energy ignition demonstration, fundamental physics research and materials processing, respectively. The requirements for these three laser systems are different necessitating different glasses or groups of glasses. The manufacturing technology is now mature for melting, annealing, fabricating and finishing of laser glasses for all three applications. The laser glass properties of major importance for HEHP, PW and HAP applications are briefly reviewed and the compositions and properties of the most widely used commercial laser glasses summarized. Proposed advances in these three laser systems will require new glasses and new melting methods which are briefly discussed. The challenges presented by these laser systems will likely dominate the field of laser glass development over the next several decades.

Campbell, J H; Hayden, J S; Marker, A J

2010-12-17T23:59:59.000Z

262

Interfacial electron and phonon scattering processes in high-powered nanoscale applications.  

SciTech Connect (OSTI)

The overarching goal of this Truman LDRD project was to explore mechanisms of thermal transport at interfaces of nanomaterials, specifically linking the thermal conductivity and thermal boundary conductance to the structures and geometries of interfaces and boundaries. Deposition, fabrication, and post possessing procedures of nanocomposites and devices can give rise to interatomic mixing around interfaces of materials leading to stresses and imperfections that could affect heat transfer. An understanding of the physics of energy carrier scattering processes and their response to interfacial disorder will elucidate the potentials of applying these novel materials to next-generation high powered nanodevices and energy conversion applications. An additional goal of this project was to use the knowledge gained from linking interfacial structure to thermal transport in order to develop avenues to control, or 'tune' the thermal transport in nanosystems.

Hopkins, Patrick E.

2011-10-01T23:59:59.000Z

263

Target isolation system, high power laser and laser peening method and system using same  

DOE Patents [OSTI]

A system for applying a laser beam to work pieces, includes a laser system producing a high power output beam. Target delivery optics are arranged to deliver the output beam to a target work piece. A relay telescope having a telescope focal point is placed in the beam path between the laser system and the target delivery optics. The relay telescope relays an image between an image location near the output of the laser system and an image location near the target delivery optics. A baffle is placed at the telescope focal point between the target delivery optics and the laser system to block reflections from the target in the target delivery optics from returning to the laser system and causing damage.

Dane, C. Brent (Livermore, CA); Hackel, Lloyd A. (Livermore, CA); Harris, Fritz (Rocklin, CA)

2007-11-06T23:59:59.000Z

264

High-power targets: experience and R&D for 2 MW  

SciTech Connect (OSTI)

High-power particle production targets are crucial elements of future neutrino and other rare particle beams. Fermilab plans to produce a beam of neutrinos (LBNE) with a 2.3 MW proton beam (Project X). Any solid target is unlikely to survive for an extended period in such an environment - many materials would not survive a single beam pulse. We are using our experience with previous neutrino and antiproton production targets, along with a new series of R&D tests, to design a target that has adequate survivability for this beamline. The issues considered are thermal shock (stress waves), heat removal, radiation damage, radiation accelerated corrosion effects, physics/geometry optimization and residual radiation.

Hurh, P.; /Fermilab; Caretta, O.; Davenne, T.; Densham, C.; Loveridge, P.; /Rutherford; Simos, N.; /Brookhaven

2011-03-01T23:59:59.000Z

265

Stimulated Raman Scattering and Nonlinear Focusing of High-Power Laser Beams Propagating in Water  

E-Print Network [OSTI]

The physical processes associated with propagation of a high-power (power > critical power for self-focusing) laser beam in water include nonlinear focusing, stimulated Raman scattering (SRS), optical breakdown and plasma formation. The interplay between nonlinear focusing and SRS is analyzed for cases where a significant portion of the pump power is channeled into the Stokes wave. Propagation simulations and an analytical model demonstrate that the Stokes wave can re-focus the pump wave after the power in the latter falls below the critical power. It is shown that this novel focusing mechanism is distinct from cross-phase focusing. While discussed here in the context of propagation in water, the gain-focusing phenomenon is general to any medium supporting nonlinear focusing and stimulated forward Raman scattering.

Hafizi, B; Penano, J R; Gordon, D F; Jones, T G; Helle, M H; Kaganovich, D

2015-01-01T23:59:59.000Z

266

High-Power Laser Pulse Recirculation for Inverse Compton Scattering-Produced Gamma-Rays  

SciTech Connect (OSTI)

Inverse Compton scattering of high-power laser pulses on relativistic electron bunches represents an attractive method for high-brightness, quasi-monoenergetic {gamma}-ray production. The efficiency of {gamma}-ray generation via inverse Compton scattering is severely constrained by the small Thomson scattering cross section. Furthermore, repetition rates of high-energy short-pulse lasers are poorly matched with those available from electron accelerators, resulting in low repetition rates for generated {gamma}-rays. Laser recirculation has been proposed as a method to address those limitations, but has been limited to only small pulse energies and peak powers. Here we propose and experimentally demonstrate an alternative method for laser pulse recirculation that is uniquely capable of recirculating short pulses with energies exceeding 1 J. Inverse Compton scattering of recirculated Joule-level laser pulses has a potential to produce unprecedented peak and average {gamma}-ray brightness in the next generation of sources.

Jovanovic, I; Shverdin, M; Gibson, D; Brown, C

2007-04-17T23:59:59.000Z

267

Method of Fabrication of High Power Density Solid Oxide Fuel Cells  

DOE Patents [OSTI]

A method for producing ultra-high power density solid oxide fuel cells (SOFCs). The method involves the formation of a multilayer structure cells wherein a buffer layer of doped-ceria is deposited intermediate a zirconia electrolyte and a cobalt iron based electrode using a colloidal spray deposition (CSD) technique. For example, a cobalt iron based cathode composed of (La,Sr)(Co,Fe)O(LSCF) may be deposited on a zirconia electrolyte via a buffer layer of doped-ceria deposited by the CSD technique. The thus formed SOFC have a power density of 1400 mW/cm.sup.2 at 600.degree. C. and 900 mW/cm.sup.2 at 700.degree. C. which constitutes a 2-3 times increased in power density over conventionally produced SOFCs.

Pham, Ai Quoc (San Jose, CA); Glass, Robert S. (Livermore, CA)

2008-09-09T23:59:59.000Z

268

A review comparing cathodic arcs and high power impulse magnetron sputtering (HiPIMS)  

DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

High power impulse magnetron sputtering (HiPIMS) has been in the center of attention over the last years as it is an emerging physical vapor deposition (PVD) technology that combines advantages of magnetron sputtering with various forms of energetic deposition of films such as ion plating and cathodic arc plasma deposition. It should not come at a surprise that many extension and variations of HiPIMS make use, intentionally or unintentionally, of previously discovered approaches to film processing such as substrate surface preparation by metal ion sputtering and phased biasing for film texture and stress control. Therefore, in this review, an overview is given on some historical developments and features of cathodic arc and HiPIMS plasmas, showing commonalities and differences. To limit the scope, emphasis is put on plasma properties, as opposed to surveying the vast literature on specific film materials and their properties.

Anders, Andre

2014-10-01T23:59:59.000Z

269

Development and Implementation of a VHF High Power Amplifier for the Multi-Channel Coherent Radar Depth Sounder/Imager System  

E-Print Network [OSTI]

............................................................................. 106 Appendix B findFrequency MATLAB Function ....................................................................... 112 Appendix C WF_First_Run MATLAB Function ........................................................................ 113 Appendix D... Vs. frequency of the driver amplifier stage operating in pulse mode for an input drive level of -8.4 dBm ............................................................................ 53 vii Figure 5.9: Measured Gain Vs. Frequency of the high...

Crowe, Reid William

2013-08-31T23:59:59.000Z

270

Terahertz Radiation from a Pipe with Small Corrugations  

SciTech Connect (OSTI)

We have studied through analytical and numerical methods the use of a relativistic electron bunch to drive a metallic beam pipe with small corrugations for the purpose of generating terahertz radiation. For the case of a pipe with dimensions that do not change along its length, we have shown that - with reasonable parameters - one can generate a narrow-band radiation pulse with frequency {approx}1 THz, and total energy of a few milli-Joules. The pulse length tends to be on the order of tens of picoseconds. We have also shown that, if the pipe radius is tapered along its length, the generated pulse will end up with a frequency chirp; if the pulse is then made to pass through a compressor, its final length can be reduced to a few picoseconds and its peak power increased to 1 GW. We have also shown that wall losses tend to be significant and need to be included in the structure design.

Bane, K.L.F.; Stupakov, G.; /SLAC

2012-01-26T23:59:59.000Z

271

Dark current mechanism of terahertz quantum-well photodetectors  

SciTech Connect (OSTI)

Dark current mechanisms of terahertz quantum-well photodetectors (THz QWPs) are systematically investigated experimentally and theoretically by measuring two newly designed structures combined with samples reported previously. In contrast to previous investigations, scattering-assisted tunneling dark current is found to cause significant contributions to total dark current. A criterion is also proposed to determine the major dark current mechanism at different peak response frequencies. We further determine background limited performance (BLIP) temperatures, which decrease both experimentally and theoretically as the electric field increases. This work gives good description of dark current mechanism for QWPs in the THz region and is extended to determine the transition fields and BLIP temperatures with response peaks from 3 to 12 THz.

Jia, J. Y.; Gao, J. H.; Hao, M. R.; Wang, T. M.; Shen, W. Z.; Zhang, Y. H., E-mail: yuehzhang@sjtu.edu.cn [Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China); Cao, J. C.; Guo, X. G. [Key Laboratory of Terahertz Solid-State Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 865 Changning Road, Shanghai 200050 (China); Schneider, H., E-mail: h.schneider@hzdr.de [Helmholtz-Zentrum Dresden-Rossendorf, Institute of Ion Beam Physics and Materials Research, P.O. Box 510119, 01314 Dresden (Germany)

2014-10-21T23:59:59.000Z

272

Terahertz radiation and second-harmonic generation from InAs: Bulk versus surface electric-field-induced contributions  

E-Print Network [OSTI]

Terahertz radiation and second-harmonic generation from InAs: Bulk versus surface electric-harmonic generation and terahertz radiation emission indicates that the observed dominant surface electric-field-induced contributions Matthew Reid, Igor V. Cravetchi, and Robert Fedosejevs Department of Electrical and Computer

Reid, Matthew

273

All-electric detection of the polarization state of terahertz laser radiation S. D. Ganichev,1,a  

E-Print Network [OSTI]

All-electric detection of the polarization state of terahertz laser radiation S. D. Ganichev,1,a W online 6 June 2008 Two types of room-temperature detectors of terahertz laser radiation have been developed which allow, in an all-electric manner, the determination of the plane of polarization of linearly

Ganichev, Sergey

274

Accepted to SPIE DSS Conference April 29-May 3, 2013, Baltimore, MD Terahertz atmospheric attenuation and continuum effects  

E-Print Network [OSTI]

Terahertz atmospheric attenuation and continuum effects David M. Slocum,*a Thomas M. Goyette,a Elizabeth J interest in the terahertz frequency region. Applications such as pollution monitoring and detection of energetic chemicals are of particular interest. Although there has been much attention to atmospheric

Massachusetts at Lowell, University of

275

Successful High Power Acceleration of the HSC Type Injector for Cancer Therapy in IMP  

E-Print Network [OSTI]

A Hybrid single cavity (HSC) linac, which is formed by combining a radio frequency quadrupole (RFQ) structure and a drift tube (DT) structure into one interdigital-H (IH) cavity, is fabricated and assembled as a proof of principle (PoP) type injector for cancer therapy synchrotron according to the series researches. The injection method of the HSC linac adopt a direct plasma injection scheme (DPIS), which is considered to be the only method for accelerating an intense current heavy ion beam produced by a laser ion source (LIS). The input beam current of the HSC was designed to be 20 milliampere (mA) C6+ ions. According to numerical simulations, the HSC linac could accelerate a 6-mA C6+ beam which meets requirement of the needed particle number for cancer therapy use (108~9 ions per pulse). The injection system adopted HSC injector with the method of DPIS can make the existing multi-turn injection system and the stripping system unnecessary, and also can make the beam pipe of the existing synchrotron magnets downsize which could reduce the whole cost of synchrotron (estimated millions dollars). Details of the measurements and evaluations of the assembled HSC linac, and the results of the high power test using a LIS with DPIS are reported in this paper.

Liang Lu

2015-03-25T23:59:59.000Z

276

Investigation of ionized metal flux in enhanced high power impulse magnetron sputtering discharges  

SciTech Connect (OSTI)

The metal ionized flux fraction and production of double charged metal ions Me{sup 2+} of different materials (Al, Cu, Fe, Ti) by High Power Impulse Magnetron Sputtering (HiPIMS) operated with and without a pre-ionization assistance is compared in the paper. The Electron Cyclotron Wave Resonance (ECWR) discharge was employed as the pre-ionization agent providing a seed of charge in the idle time of HiPIMS pulses. A modified grid-free biased quartz crystal microbalance was used to estimate the metal ionized flux fraction ?. The energy-resolved mass spectrometry served as a complementary method to distinguish particular ion contributions to the total ionized flux onto the substrate. The ratio between densities of doubly Me{sup 2+} and singly Me{sup +} charged metal ions was determined. It is shown that ECWR assistance enhances Me{sup 2+} production with respect of absorbed rf-power. The ECWR discharge also increases the metal ionized flux fraction of about 30% especially in the region of lower pressures. Further, the suppression of the gas rarefaction effect due to enhanced secondary electron emission of Me{sup 2+} was observed.

Stranak, Vitezslav, E-mail: stranak@prf.jcu.cz [Faculty of Science, University of South Bohemia, Branisovska 31, 37005 Ceske Budejovice (Czech Republic); Hubicka, Zdenek; Cada, Martin [Institute of Physics v. v. i., Academy of Science of the Czech Republic, Na Slovance 2, 182 21 Prague (Czech Republic); Drache, Steffen; Hippler, Rainer [Institut für Physik, Ernst-Moritz-Arndt-Universität Greifswald, Felix-Hausdorff-Str. 6, 17489 Greifswald (Germany); Tichy, Milan [Faculty of Mathematics and Physics, Charles University in Prague, V Holesovickach 2, 180 00 Prague (Czech Republic)

2014-04-21T23:59:59.000Z

277

Boron-rich plasma by high power impulse magnetron sputtering of lanthanum hexaboride  

SciTech Connect (OSTI)

Boron-rich plasmas have been obtained using a LaB{sub 6} target in a high power impulse sputtering (HiPIMS) system. The presence of {sup 10}B{sup +}, {sup 11}B{sup +}, Ar{sup 2+}, Ar{sup +}, La{sup 2+}, and La{sup +} and traces of La{sup 3+}, {sup 12}C{sup +}, {sup 14}N{sup +}, and {sup 16}O{sup +} have been detected using an integrated mass and energy spectrometer. Peak currents as low as 20 A were sufficient to obtain plasma dominated by {sup 11}B{sup +} from a 5 cm planar magnetron. The ion energy distribution function for boron exhibits an energetic tail extending over several 10 eV, while argon shows a pronounced peak at low energy (some eV). This is in agreement with models that consider sputtering (B, La) and gas supply (from background and 'recycling'). Strong voltage oscillations develop at high current, greatly affecting power dissipation and plasma properties.

Oks, Efim M. [State University of Control Systems and Radioelectronics, Tomsk (Russian Federation); Anders, Andre [Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

2012-10-15T23:59:59.000Z

278

Neutronic and thermal calculation of blanket for high power operating condition of fusion reactor  

SciTech Connect (OSTI)

Internal (breeding region) structures of ceramic breeder blanket to accommodate high power operating conditions such as a DEMO reactor have been investigated. The conditions considered here are the maximum neutron wall load of 2.8 MW/m{sup 2} at outboard midplane corresponding to a fusion power of 3.0 GW and the coolant temperature of 200{degrees}C. Structure of a blanket is based on the layered pebble bed concept, which has been proposed by Japan since the ITER CDA. Lithium oxide with 50% enriched {sup 6}Li is used in a shape of small spherical pebbles which are filled in a 316SS can avoid its compatibility issue with Be. Beryllium around the breeder can is filled also in a shape of spherical pebbles which works not only as a neutron multiplier but also as a thermal resistant layer to maintain breeder temperature for effective in-situ tritium recovery. Diameters and packing fractions of both pebbles are {<=} 1 mm and 65%, respectively. A layer of block Be between cooling panels is introduced as a neutron multiplier (not as the thermal resistant layer) to enhance tritium breeding performance. Inlet temperature of water coolant is 200{degrees}C to meet the high temperature conditioning requirement to the first wall which is one of walls of the blanket vessel. Neutronics calculations have been carried out by one-dimensional transport code, and thermal calculations have also been carried out by one-dimensional slab code.

Sagawa, H.; Shimakawa, S.; Kuroda, T. [Oarai Research Establishement of JAERI, Ibaraki (Japan)] [and others

1994-12-31T23:59:59.000Z

279

HIGH POWER TEST OF RF SEPARATOR FOR 12 GEV UPGRADE OF CEBAF AT JLAB  

SciTech Connect (OSTI)

CEBAF at JLab is in the process of an energy upgrade from 6 GeV to 12 GeV. The existing setup of the RF separator cavities in the 5th pass will not be adequate to extract the highest energy (11 GeV) beam to any two existing halls (A, B or C) while simultaneously delivering to the new hall D in the case of the proposed 12 GeV upgrade of the machine. To restore this capability, we are exploring the possibility of extension of existing normal conducting 499 MHz TEM-type rf separator cavities. Detailed numerical studies suggest that six 2-cell normal conducting structures meet the requirements; each 2-cell structure will require up to 4 kW RF input power in contrast with the current nominal operating power of 1.0 to 2.0 kW. A high power test of 4 kW confirms that the cavity meet the requirement.

S. Ahmed, M. Wissmann, J. Mammosser, C. Hovater, M. Spata, G. Krafft, J. Delayen

2012-07-01T23:59:59.000Z

280

MODEL AND BEAM BASED SETUP PROCEDURES FOR A HIGH POWER HADRON SUPERCONDUCTING LINAC  

SciTech Connect (OSTI)

This presentation will review methods for experimental determination of optimal operational set points in a multi-cavity superconducting high power hadron linac. A typical tuning process is based on comparison between measured data and the results of simulations from envelope and single-particle models. Presence of significant space charge effects requires simulation and measurement of bunch dynamics in 3 dimensions to ensure low loss beam transport. This is especially difficult in a superconducting linac where use of interceptive diagnostics is usually restricted because of the risk of SRF cavity surface contamination. The procedures discussed here are based on non-interceptive diagnostics such as beam position monitors and laser wires, and conventional diagnostics devices such as wire scanners and bunch shape monitors installed outside the superconducting linac. The longitudinal Twiss analysis based on the BPM signals will be described. The superconducting SNS linac tuning experience will be used to demonstrate problems and their solution for real world linac tune-up procedures

Shishlo, Andrei P [ORNL

2014-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "high-power coherent terahertz" from the National Library of EnergyBeta (NLEBeta).
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We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

Air Electrode Design for Sustained High Power Operation of Li/air Batteries  

SciTech Connect (OSTI)

The rapid development of portable electronic devices increasingly requires much more energy to support advanced functions. However, currently available batteries do not meet the high energy requirement of these devices. Metal/air batteries, especially Li/air batteries, have a much higher specific energy than most other available batteries, but their power rate is limited by the accumulation of reaction products in the air electrode. Several approaches to improve the power rate of Li/air batteries have been analyzed in this work, including adjustment of air electrode porosity and catalyst reactivity distributions to minimize diffusion limitations and maximize air electrode material utilization. An interconnected dual pore system (one catalyzed and one noncatalyzed) is proposed to improve oxygen transport into the inner regions of the air electrode, but this approach alone cannot supply high power for long term applications. A time-release multiple catalyst approach is analyzed to provide temporal release of reactivity in the air electrode. When coupled with the dual pore configuration and catalysts with high reactivities, the time-release catalyst concept can extend the duration of higher powers to longer times, and result in maximum utilization of air electrode materials.

Williford, Ralph E.; Zhang, Jiguang

2009-08-31T23:59:59.000Z

282

RF Distribution System for High Power Test of the SNS Cryomodule  

SciTech Connect (OSTI)

A four-way waveguide RF power distribution system for testing the Spallation Neutron Source (SNS) multi-cavity cryomodule to investigate the collective behavior has been developed. A single klystron operating at 805MHz for 1.3 msec at 60Hz powers the 4-way waveguide splitter to deliver up to 400 kW to individual cavities. Each cavity is fed through a combination of waveguide splitters and vector modulators (VM) to provide independent magnitude and phase controls. The waveguide vector modulator consists of two quadrature hybrids and two motorized waveguide phase shifters. The phase shifters and the assembled waveguide vector modulators were individually tested and characterized for low power and high RF power in the SNS RF test facility. Precise calibrations of magnitude and phase were performed to generate the look up tables (LUTs) to provide operational references during the cryomodule test. An I-Q demodulator module was developed and utilized to measure relative phases in pulsed high RF power operation. PLC units were developed for mechanical control of the phase shifters. Initial low/high power measurements were made using LabVIEW. An operation algorithm has been implemented into EPICS control for the cryomodule test stand.

Lee, Sung-Woo [ORNL] [ORNL; Kang, Yoon W [ORNL] [ORNL; Broyles, Michael R [ORNL] [ORNL; Crofford, Mark T [ORNL] [ORNL; Geng, Xiaosong [ORNL] [ORNL; Kim, Sang-Ho [ORNL] [ORNL; Phibbs, Curtis L [ORNL] [ORNL; Strong, William Herb [ORNL] [ORNL; Peglow, Robert C [ORNL] [ORNL; Vassioutchenko, Alexandre V [ORNL] [ORNL

2012-01-01T23:59:59.000Z

283

APEX and ALPS, high power density technology programs in the U.S.  

SciTech Connect (OSTI)

In fiscal year (FY) 1998 two new fusion technology programs were initiated in the US, with the goal of making marked progress in the scientific understanding of technologies and materials required to withstand high plasma heat flux and neutron wall loads. APEX is exploring new and revolutionary concepts that can provide the capability to extract heat efficiently from a system with high neutron and surface heat loads while satisfying all the fusion power technology requirements and achieving maximum reliability, maintainability, safety, and environmental acceptability. ALPS program is evaluating advanced concepts including liquid surface limiters and divertors on the basis of such factors as their compatibility with fusion plasma, high power density handling capabilities, engineering feasibility, lifetime, safety and R and D requirements. The APEX and ALPS are three-year programs to specify requirements and evaluate criteria for revolutionary approaches in first wall, blanket and high heat flux component applications. Conceptual design and analysis of candidate concepts are being performed with the goal of selecting the most promising first wall, blanket and high heat flux component designs that will provide the technical basis for the initiation of a significant R and D effort beginning in FY2001. These programs are also considering opportunities for international collaborations.

Wong, C. [General Atomics, San Diego, CA (United States). Fusion Group; Berk, S. [Dept. of Energy, Washington, DC (United States). Office of Fusion Energy Sciences; Abdou, M. [Univ. of California, Los Angeles, CA (United States). School of Engineering and Applied Science; Mattas, R. [Argonne National Lab., IL (United States). Fusion Power Program

1999-02-01T23:59:59.000Z

284

Coherent control of neutron interferometry  

E-Print Network [OSTI]

In this thesis, several novel techniques are proposed and demonstrated for measuring the coherent properties of materials and testing aspects of quantum information processing using a single crystal neutron interferometer. ...

Pushin, Dmitry A

2007-01-01T23:59:59.000Z

285

Beam manipulation techniques, nonlinear beam dynamics, and space charge effect in high energy high power accelerators  

SciTech Connect (OSTI)

We had carried out a design of an ultimate storage ring with beam emittance less than 10 picometer for the feasibility of coherent light source at X-ray wavelength. The accelerator has an inherent small dynamic aperture. We study method to improve the dynamic aperture and collective instability for an ultimate storage ring. Beam measurement and accelerator modeling are an integral part of accelerator physics. We develop the independent component analysis (ICA) and the orbit response matrix method for improving accelerator reliability and performance. In collaboration with scientists in National Laboratories, we also carry out experimental and theoretical studies on beam dynamics. Our proposed research topics are relevant to nuclear and particle physics using high brightness particle and photon beams.

Lee, S. Y.

2014-04-07T23:59:59.000Z

286

Fully-automatic laser welding and micro-sculpting with universal in situ inline coherent imaging  

E-Print Network [OSTI]

Though new affordable high power laser technologies make possible many processing applications in science and industry, depth control remains a serious technical challenge. Here we show that inline coherent imaging, with line rates up to 312 kHz and microsecond-duration capture times, is capable of directly measuring laser penetration depth in a process as violent as kW-class keyhole welding. We exploit ICI's high speed, high dynamic range and robustness to interference from other optical sources to achieve fully automatic, adaptive control of laser welding as well as ablation, achieving micron-scale sculpting in vastly different heterogeneous biological materials.

Webster, Paul J L; Ji, Yang; Galbraith, Christopher M; Kinross, Alison W; Van Vlack, Cole; Fraser, James M

2014-01-01T23:59:59.000Z

287

Laser beat wave excitation of terahertz radiation in a plasma slab  

SciTech Connect (OSTI)

Terahertz (THz) radiation generation by nonlinear mixing of lasers, obliquely incident on a plasma slab is investigated. Two cases are considered: (i) electron density profile is parabolic but density peak is below the critical density corresponding to the beat frequency, (ii) plasma boundaries are sharp and density is uniform. In both cases, nonlinearity arises through the ponderomotive force that gives rise to electron drift at the beat frequency. In the case of inhomogeneous plasma, non zero curl of the nonlinear current density gives rise to electromagnetic THz generation. In case of uniform plasma, the sharp density variation at the plasma boundaries leads to radiation generation. In a slab width of less than a terahertz wavelength, plasma density one fourth of terahertz critical density, laser intensities ?10{sup 17?}W/cm{sup 2} at 1??m, one obtains the THz intensity ?1?GW/cm{sup 2} at 3 THz radiation frequency.

Chauhan, Santosh; Parashar, Jetendra, E-mail: j.p.parashar@gmail.com [Department of Applied Physics, Samrat Ashok Technological Institute, Vidisha 464001, Madhya Pradesh (India)

2014-10-15T23:59:59.000Z

288

Quantum coherence and correlations in quantum system  

E-Print Network [OSTI]

Criteria of measure quantifying quantum coherence, a unique property of quantum system, are proposed recently. In this paper, we firstly give an uncertainty-like expression relating the coherence and the entropy of quantum system. Then, we obtain three trade-offs among the coherence, the discord and the deficit in the bipartite quantum system.As a consequence, we obtain that the relative entropy of coherence satisfies the super-additivity. Finally, we discuss the relations between the entanglement and the coherence.

Zhengjun Xi; Yongming Li; Heng Fan

2014-12-24T23:59:59.000Z

289

A thermally self-sustained micro solid-oxide fuel-cell stack with high power density  

E-Print Network [OSTI]

A thermally self-sustained micro solid-oxide fuel-cell stack with high power density Zongping Shao1 for portable power generation1,2 . Accordingly, polymer-electrolyte direct- methanol fuel cells design challenges and cannot operate with hydrocarbon fuels of higher energy density. Solid-oxide fuel

Haile, Sossina M.

290

High-power ELF radiation generated by modulated HF heating of the ionosphere can cause Earthquakes, Cyclones and localized heating  

E-Print Network [OSTI]

High-power ELF radiation generated by modulated HF heating of the ionosphere can cause Earthquakes, the HAARP heater is the most powerful ionospheric heater, with 3.6GW of effective power using HF heating, Cyclones and localized heating Fran De Aquino Maranhao State University, Physics Department, S

Paris-Sud XI, Université de

291

HIGH-POWER PRECISION CURRENT SUPPLY IST2-1000M FOR ELEMENTS OF MAGNETIC SYSTEMS OF ACCELERATORS AND  

E-Print Network [OSTI]

HIGH-POWER PRECISION CURRENT SUPPLY IST2-1000M FOR ELEMENTS OF MAGNETIC SYSTEMS OF ACCELERATORS. These supplies are intended to power magnetic systems of accelerators, requiring high stability and low ripples for active suppression of pulsation A/s 100 The Supply consists of two boxes (power box PB and box of filters

Kozak, Victor R.

292

Technology Survey and Performance Scaling for the Design of High Power Nuclear Electric Power and Propulsion Systems  

E-Print Network [OSTI]

, use of electric primary propulsion in flight systems has been limited to low-power, solar electric thruster output power are identified. Design evolutions are presented for three thrusters that would1 Technology Survey and Performance Scaling for the Design of High Power Nuclear Electric Power

293

KT McDonald Snowmass Frontier Workshop (BNL) Apr 19, 2013 1 The High-Power-Target System  

E-Print Network [OSTI]

KT McDonald Snowmass Frontier Workshop (BNL) Apr 19, 2013 1 The High-Power-Target System of a Muon Collider or Neutrino Factory K. McDonald Princeton U. (April 19, 2013) Snowmass Workshop on Frontier Capability Brookhaven National Laboratory #12;KT McDonald Snowmass Frontier Workshop (BNL) Apr 19, 2013 2

McDonald, Kirk

294

Single-Frequency High-Power Continuous-Wave Oscillation at 1003 nm of an Optically Pumped Semiconductor Laser  

E-Print Network [OSTI]

reduction of the thermal resistance of the active semiconductor medium, resulting in a high power laser powers [1,2]. However the poor thermal conductivity of III-V materials might prevent an efficient heat by bonding it to a material of high thermal conductivity and good optical quality [2,4,5]. In this work we

Boyer, Edmond

295

High-power liquid-lithium jet target for neutron production  

SciTech Connect (OSTI)

A compact liquid-lithium target (LiLiT) was built and tested with a high-power electron gun at the Soreq Nuclear Research Center. The lithium target, to be bombarded by the high-intensity proton beam of the Soreq Applied Research Accelerator Facility (SARAF), will constitute an intense source of neutrons produced by the {sup 7}Li(p,n){sup 7}Be reaction for nuclear astrophysics research and as a pilot setup for accelerator-based Boron Neutron Capture Therapy. The liquid-lithium jet target acts both as neutron-producing target and beam dump by removing the beam thermal power (>5 kW, >1 MW/cm{sup 3}) with fast transport. The target was designed based on a thermal model, accompanied by a detailed calculation of the {sup 7}Li(p,n) neutron yield, energy distribution, and angular distribution. Liquid lithium is circulated through the target loop at ?200 °C and generates a stable 1.5 mm-thick film flowing at a velocity up to 7 m/s onto a concave supporting wall. Electron beam irradiation demonstrated that the liquid-lithium target can dissipate electron power areal densities of >4 kW/cm{sup 2} and volume power density of ?2 MW/cm{sup 3} at a lithium flow of ?4 m/s while maintaining stable temperature and vacuum conditions. The LiLiT setup is presently in online commissioning stage for high-intensity proton beam irradiation (1.91–2.5 MeV, 1–2 mA) at SARAF.

Halfon, S.; Feinberg, G. [Soreq NRC, Yavne 81800 (Israel) [Soreq NRC, Yavne 81800 (Israel); Racah Institute of Physics, Hebrew University, Jerusalem 91904 (Israel); Arenshtam, A.; Kijel, D.; Berkovits, D.; Eliyahu, I.; Hazenshprung, N.; Mardor, I.; Nagler, A.; Shimel, G.; Silverman, I. [Soreq NRC, Yavne 81800 (Israel)] [Soreq NRC, Yavne 81800 (Israel); Paul, M.; Friedman, M.; Tessler, M. [Racah Institute of Physics, Hebrew University, Jerusalem 91904 (Israel)] [Racah Institute of Physics, Hebrew University, Jerusalem 91904 (Israel)

2013-12-15T23:59:59.000Z

296

Study of second harmonic generation by high power laser beam in magneto plasma  

SciTech Connect (OSTI)

This paper examines the problem of nonlinear generation of second harmonic of a high power laser pulse propagating in magnetized plasma. The propagation of strong laser beam is proposed in the direction perpendicular to a relatively weak static magnetic field. The laser pulse is taken to be linearly polarized, with the orientation of its electric field that corresponds to an ordinary electromagnetic wave. Besides the standard ponderomotive nonlinearity, the appropriate wave equation also contains the nonlinearity that arises from the relativistic electron jitter velocities. During its propagation, the laser beam gets filamented on account of relativistic and pondermotive nonlinearities present in the plasma. The generated plasma wave gets coupled into the filamentary structures of the pump beam. Due to the expected presence of the beam filamentation, the work has been carried out by considering modified paraxial approximation (i.e., beyond the standard paraxial approximation of a very broad beam). It is found that the power of the plasma wave is significantly affected by the magnetic field strength in the presence of both relativistic and pondermotive nonlinearities. It is investigated that the second harmonic generation is also considerably modified by altering the strength of magnetic field. To see the effect of static magnetic field on the harmonic generation, a key parameter, i.e., the ratio of the cyclotron frequency {omega}{sub c}=eB{sub 0}/mc over the laser frequency {omega}{sub 0} has been used, where c is the velocity of light, m and e are the mass and charge of the electron and B{sub 0} is the externally applied magnetic field.

Sharma, Prerana [Ujjain Engineering College, Ujjain, Madhya Pradesh 465010 (India); Sharma, R. P. [Centre for Energy Studies, Indian Institute of Technology, New Delhi 110016 (India)

2012-12-15T23:59:59.000Z

297

A high power beam-on-target test of liquid lithium target for RIA.  

SciTech Connect (OSTI)

Experiments were conducted to demonstrate the stable operation of a windowless liquid lithium target under extreme thermal loads that are equivalent to uranium beams from the proposed Rare Isotope Accelerator (RIA) driver linac. The engineering and safety issues accompanying liquid lithium systems are first discussed. The liquid metal technology knowledge base generated primarily for fast reactors, and liquid metal cooled fusion reactors, was applied to the development of these systems in a nuclear physics laboratory setting. The use of a high energy electron beam for simulating a high power uranium beam produced by the RIA driver linac is also described. Calculations were performed to obtain energy deposition profiles produced by electron beams at up to a few MeV to compare with expected uranium beam energy deposition profiles. It was concluded that an experimental simulation using a 1-MeV electron beam would be a valuable tool to assess beam-jet interaction. In the experiments, the cross section of the windowless liquid lithium target was 5 mm x 10 mm, which is a 1/3rd scale prototype target, and the velocity of the liquid lithium was varied up to 6 m/s. Thermal loads up to 20 kW within a beam spot diameter of 1mm were applied on the windowless liquid lithium target by the 1-MeV electron beam. The calculations showed that the maximum power density and total power deposited within the target, from the electron beam, was equivalent to that of a 200-kW, 400-MeV/u uranium beam. It was demonstrated that the windowless liquid lithium target flowing at velocities as low as 1.8 m/s stably operated under beam powers up to 20 kW without disruption or excessive vaporization.

Nolen, J.; Reed, C.; Novick, V.; Specht, J.; Plotkin, P.; Momozaki,Y.; Gomes, I.

2005-08-29T23:59:59.000Z

298

Use of the LEDA Facility as an ADS High-Power Accelerator Test Bed  

SciTech Connect (OSTI)

The Low-Energy Demonstration Accelerator (LEDA) was built to generate high-current proton beams. Its successful full-power operation and testing in 1999-2001 confirmed the feasibility of a high-power linear accelerator (linac) front end, the most technically challenging portion of such a machine. The 6.7-MeV accelerator operates reliably at 95-mA CW beam current with few interruptions orjaults, and qualiJes as one of the most powerful accelerators in the world. LEDA is now available to address the needs of other programs. LEDA can be upgraded in a staged fashion to allow for full-power accelerator demonstrations. The proposed post-h!FQ accelerator structures are 350-MHz superconducting spoke cavities developed for the AAA /APT program. The superconducting portion of the accelerator is designed for a IOO-mA proton beam current. Superconducting cavities were chosen because of the signijkant thermal issues with room-temperature structures, the larger superconducting cavity apertures, and the lower operating costs ('because of improved electrical efficiency) of a superconducting accelerator. Since high reliability is a major issue for an ADS system, the superconducting design architecture alIows operation through faults due to the failure of single magnets or superconducting cavities. The presently installed power capacity of 13 MVA of input ACpower is capable of supporting a 40-MeVproton beam at 100 mA. (The input power is easily expandable to 25 MVA, allowing up to 100-MeV operation). Operation at 40-MeV would provide a complete demonstration of all of the critical accelerator sub-systems ofa full-power ADS system.

Garnett, R. W. (Robert W.); Sheffield, R. L. (Richard L.)

2003-01-01T23:59:59.000Z

299

Durability of Low Platinum Fuel Cells Operating at High Power Density  

SciTech Connect (OSTI)

Understanding and improving the durability of cost-competitive fuel cell stacks is imperative to successful deployment of the technology. Stacks will need to operate well beyond today’s state-of-the-art rated power density with very low platinum loading in order to achieve the cost targets set forth by DOE ($15/kW) and ultimately be competitive with incumbent technologies. An accelerated cost-reduction path presented by Nuvera focused on substantially increasing power density to address non-PGM material costs as well as platinum. The study developed a practical understanding of the degradation mechanisms impacting durability of fuel cells with low platinum loading (?0.2mg/cm2) operating at high power density (?1.0W/cm2) and worked out approaches for improving the durability of low-loaded, high-power stack designs. Of specific interest is the impact of combining low platinum loading with high power density operation, as this offers the best chance of achieving long-term cost targets. A design-of-experiments approach was utilized to reveal and quantify the sensitivity of durability-critical material properties to high current density at two levels of platinum loading (the more conventional 0.45 mgPt.cm–1 and the much lower 0.2 mgPt.cm–2) across several cell architectures. We studied the relevance of selected component accelerated stress tests (AST) to fuel cell operation in power producing mode. New stress tests (NST) were designed to investigate the sensitivity to the addition of electrical current on the ASTs, along with combined humidity and load cycles and, eventually, relate to the combined city/highway drive cycle. Changes in the cathode electrochemical surface area (ECSA) and average oxygen partial pressure on the catalyst layer with aging under AST and NST protocols were compared based on the number of completed cycles. Studies showed elevated sensitivity of Pt growth to the potential limits and the initial particle size distribution. The ECSA loss was correlated with the upper potential limit in the cycle tests, although the performance degradation was found to be a strong function of initial Pt loading. A large fraction of the voltage degradation was found due to increased mass transfer overpotentials, especially in the lower Pt loading cells. Increased mass transfer overpotentials were responsible for a large fraction of the voltage degradation at high current densities. Analysis of the impedance and polarization data indicated O2 diffusion in the aged electrode ionomer to be the main source of the increased mass transfer overpotentials. Results from the experimental parametric studies were used to inform and calibrate newly developed durability model, simulating lifetime performance of the fuel cell under variety of load-cycle protocols, electrode loadings and throughout wide range of operating conditions, including elevated-to-3.0A/cm2 current densities. Complete durability model included several sub-models: platinum dissolution-and-growth as well as reaction-diffusion model of cathode electrode, applied sequentially to study the lifetime predictions of ECSA and polarization performance in the ASTs and NSTs. These models establish relations between changes in overpotentials, ECSA and oxygen mass transport in fuel cell cathodes. The model was calibrated using single cells with land-channel and open flowfield architectures. The model was validated against Nuvera Orion® (open flowfield) short stack data in the load cycle durability tests. The reaction-diffusion model was used to correlate the effective mass transfer coefficients for O2 diffusion in cathode ionomer and separately in gas pores with the operating conditions (pressure, temperature, gas velocity in flow field and current density), Pt loading, and ageing related growth in Pt particles and thinning of the electrode. Achievements of both modeling and experimental objectives were demonstrated in a full format, subscale stacks operating in a simulated but fully realistic ambient environment, using system-compatible operating protocols.

Polevaya, Olga [Nuvera Fuel Cells Inc.] [Nuvera Fuel Cells Inc.; Blanchet, Scott [Nuvera Fuel Cells Inc.] [Nuvera Fuel Cells Inc.; Ahluwalia, Rajesh [Argonne National Lab] [Argonne National Lab; Borup, Rod [Los-Alamos National Lab] [Los-Alamos National Lab; Mukundan, Rangachary [Los-Alamos National Lab] [Los-Alamos National Lab

2014-03-19T23:59:59.000Z

300

Vol. 11, No. 12/December 1994/J. Opt. Soc. Am. B 2457 Coherent control of terahertz emission and carrier  

E-Print Network [OSTI]

when the exciting optical fields are shaped in both amplitude and phase. Our shaping techniques include phase-locked pulse generation in a Michelson interferometer and pulse-train generation by phase state is determined by the exciting optical field. This phase can be lost by a variety of processes

Purdue University

Note: This page contains sample records for the topic "high-power coherent terahertz" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

Aqueous blackbody calibration source for millimeter-wave/terahertz metrology  

SciTech Connect (OSTI)

This paper describes a calibrated broadband emitter for the millimeter-wave through terahertz frequency regime, called the aqueous blackbody calibration source. Due to its extremely high absorption, liquid water is chosen as the emitter on the basis of reciprocity. The water is constrained to a specific shape (an optical trap geometry) in an expanded polystyrene (EPS) container and maintained at a selected, uniform temperature. Uncertainty in the selected radiometric temperature due to the undesirable reflectance present at a water interface is minimized by the trap geometry, ensuring that radiation incident on the entrance aperture encounters a pair of s and a pair of p reflections at 45 deg. . For water reflectance Rw of 40% at 45 deg. in W-band, this implies a theoretical effective aperture emissivity of (1-R{sup 2}wsR{sup 2}wp)>98.8%. From W-band to 450 GHz, the maximum radiometric temperature uncertainty is {+-}0.40 K, independent of water temperature. Uncertainty from 450 GHz to 1 THz is increased due to EPS scattering and absorption, resulting in a maximum uncertainty of -3 K at 1 THz.

Dietlein, Charles; Popovic, Zoya; Grossman, Erich N

2008-10-20T23:59:59.000Z

302

Tuning the response of terahertz metamaterial at low temperatures  

SciTech Connect (OSTI)

The transmission response of planar thin film metamateriaJs were measured at room and liquid nitrogen temperatures using terahertz time-domain spectroscopy. The behaviour of metamaterials at low temperatures is shown to have low-loss since the nonradiative losses are strongly suppressed due to higher metal film conductivity. We observe a temperature tunable effect and a gradual increase of 40% in the quality factor of the metamaterial. The emerging field of metamaterial (MM) has opened a gateway to unprecedented electromagnetic properties and functionality unattainable from naturally occurring materials. Planar metamaterials are made of thin metal films with a thickness comparable to the skin depth. In spite of several newly found potential applications of these metafilms, practical use is often hindered by strong losses of the metallic elements. It causes a weakening and a damping of the resonance. This makes dissipation the property that dominates the light propagation. Therefore, the compensation of such losses is currently the most important topic to solve prior to advancing MMs to a higher level. Overall metamaterial losses typically have a radiative contribution, which can be tailored by suitable geometrical modifications, and a non-radiative contribution, associated to the intrinsic absorption of the light in the metal and/or dielectric. Thus, one way to improve their performance is to increase the conductivity of the metals. A simple technique to increase the metal conductivity is to cool it to low temperatures.

Singh, Ranjan [Los Alamos National Laboratory; O' Hara, John F [Los Alamos National Laboratory; Taylor, Antoinette [Los Alamos National Laboratory; Zhang, Weili [OKLAHOMA STATE UNIV; Tian, Zhen [OKLAHOMA STATE UNIV; Han, Jiaguang [NATIONAL UNIV OF SINGAPORE; Rockstukl, Carsten [FRIEDRICH-SCHILLER-UNIV JENA; Gu, Jianqiang [OKLAHOMA STATE UNIV

2010-01-01T23:59:59.000Z

303

Graphene-based terahertz tunable plasmonic directional coupler  

SciTech Connect (OSTI)

We propose and numerically analyze a terahertz tunable plasmonic directional coupler which is composed of a thin metal film with a nanoscale slit, dielectric grating, a graphene sheet, and a dielectric substrate. The slit is employed to generate surface plasmon polaritons (SPPs), and the metal-dielectric grating-graphene-dielectric constructs a Bragg reflector, whose bandgap can be tuned over a wide frequency range by a small change in the Fermi energy level of graphene. As a graphene-based Bragg reflector is formed on one side of the slit, the structure enables SPP waves to be unidirectionally excited on the other side of the slit due to SPP interference, and the SPP waves in the Bragg reflector can be efficiently switched on and off by tuning the graphene's Fermi energy level. By introducing two optimized graphene-based Bragg reflectors into opposite sides of the slit, SPP waves can be guided to different Bragg reflectors at different Fermi energy levels, thus achieving a tunable bidirectional coupler.

He, Meng-Dong, E-mail: hemendong@sohu.com; Wang, Kai-Jun; Wang, Lei; Li, Jian-Bo [Institute of Mathematics and Physics, Central South University of Forestry and Technology, Changsha 410004 (China); Liu, Jian-Qiang [College of Science, Jiujiang University, Jiujiang 332005 (China); Huang, Zhen-Rong; Wang, Lingling [Key Laboratory for Micro-Nano Optoelectronic Devices of Ministry of Education, Hunan University, Changsha 410082 (China); Wang, Lin; Hu, Wei-Da; Chen, Xiaoshuang [National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Science, Shanghai 200083 (China)

2014-08-25T23:59:59.000Z

304

Composite Cathode for High-Power Density Solid Oxide Fuel Cells  

SciTech Connect (OSTI)

Reduction of solid oxide fuel cell (SOFC) operating temperature will play a key role in reducing the stack cost by allowing the use of low-cost metallic interconnects and new approaches to sealing, while making applications such as transportation more feasible. Reported results for anode-supported SOFCs show that cathode polarization resistance is the primary barrier to achieving high power densities at operating temperatures of 700 C and lower. This project aims to identify and develop composite cathodes that could reduce SOFC operating temperatures below 700 C. This effort focuses on study and use of (La,Sr)(Co,Fe)O{sub 3} (LSCF) based composite cathodes, which have arguably the best potential to substantially improve on the currently-used, (La,Sr)MnO{sub 3}-Yttria-stabilized Zirconia. During this Phase I, it was successfully demonstrated that high performances can be achieved with LSCF/Gadolinium-Doped Ceria composite cathodes on Ni-based anode supported cells operating at 700 C or lower. We studied electrochemical reactions at LSCF/Yttria-stabilized Zirconia (YSZ) interfaces, and observed chemical reactions between LSCF and YSZ. By using ceria electrolytes or YSZ electrolytes with ceria diffusion barrier layers, the chemical reactions between LSCF and electrolytes were prevented under cathode firing conditions necessary for the optimal adhesion of the cathodes. The protection provided by ceria layer is expected to be adequate for stable long-term cathode performances, but more testing is needed to verify this. Using ceria-based barrier layers, high performance Ni-YSZ anode supported cells have been demonstrated with maximum power densities of 0.8W/cm2 at 700 C and 1.6W/cm{sup 2} at 800 C. Ni-SDC anode supported cells with SDC electrolytes yielded >1W/cm{sup 2} at 600 C. We speculate that the power output of Ni-YSZ anode supported cell at 700 C and lower, was limited by the quality of the Ceria and Ceria YSZ interface. Improvements in the low-temperature performances are expected based on further development of barrier layer fabrication processes and optimization of cathode microstructure.

Ilwon Kim; Scott Barnett; Yi Jiang; Manoj Pillai; Nikkia McDonald; Dan Gostovic; Zhongryang Zhan; Jiang Liu

2004-01-31T23:59:59.000Z

305

HIGH-POWER TURBODRILL AND DRILL BIT FOR DRILLING WITH COILED TUBING  

SciTech Connect (OSTI)

Commercial introduction of Microhole Technology to the gas and oil drilling industry requires an effective downhole drive mechanism which operates efficiently at relatively high RPM and low bit weight for delivering efficient power to the special high RPM drill bit for ensuring both high penetration rate and long bit life. This project entails developing and testing a more efficient 2-7/8 in. diameter Turbodrill and a novel 4-1/8 in. diameter drill bit for drilling with coiled tubing. The high-power Turbodrill were developed to deliver efficient power, and the more durable drill bit employed high-temperature cutters that can more effectively drill hard and abrasive rock. This project teams Schlumberger Smith Neyrfor and Smith Bits, and NASA AMES Research Center with Technology International, Inc (TII), to deliver a downhole, hydraulically-driven power unit, matched with a custom drill bit designed to drill 4-1/8 in. boreholes with a purpose-built coiled tubing rig. The U.S. Department of Energy National Energy Technology Laboratory has funded Technology International Inc. Houston, Texas to develop a higher power Turbodrill and drill bit for use in drilling with a coiled tubing unit. This project entails developing and testing an effective downhole drive mechanism and a novel drill bit for drilling 'microholes' with coiled tubing. The new higher power Turbodrill is shorter, delivers power more efficiently, operates at relatively high revolutions per minute, and requires low weight on bit. The more durable thermally stable diamond drill bit employs high-temperature TSP (thermally stable) diamond cutters that can more effectively drill hard and abrasive rock. Expectations are that widespread adoption of microhole technology could spawn a wave of 'infill development' drilling of wells spaced between existing wells, which could tap potentially billions of barrels of bypassed oil at shallow depths in mature producing areas. At the same time, microhole coiled tube drilling offers the opportunity to dramatically cut producers' exploration risk to a level comparable to that of drilling development wells. Together, such efforts hold great promise for economically recovering a sizeable portion of the estimated remaining shallow (less than 5,000 feet subsurface) oil resource in the United States. The DOE estimates this U.S. targeted shallow resource at 218 billion barrels. Furthermore, the smaller 'footprint' of the lightweight rigs utilized for microhole drilling and the accompanying reduced drilling waste disposal volumes offer the bonus of added environmental benefits. DOE analysis shows that microhole technology has the potential to cut exploratory drilling costs by at least a third and to slash development drilling costs in half.

Robert Radtke; David Glowka; Man Mohan Rai; David Conroy; Tim Beaton; Rocky Seale; Joseph Hanna; Smith Neyrfor; Homer Robertson

2008-03-31T23:59:59.000Z

306

Practical Witness for Electronic Coherences  

E-Print Network [OSTI]

The origin of the coherences in two-dimensional spectroscopy of photosynthetic complexes remains disputed. Recently it has been shown that in the ultrashort-pulse limit, oscillations in a frequency-integrated pump-probe signal correspond exclusively to electronic coherences, and thus such experiments can be used to form a test for electronic vs. vibrational oscillations in such systems. Here we demonstrate a method for practically implementing such a test, whereby pump-probe signals are taken at several different pulse durations and used to extrapolate to the ultrashort-pulse limit. We present analytic and numerical results determining requirements for pulse durations and the optimal choice of pulse central frequency, which can be determined from an absorption spectrum. Our results suggest that for numerous systems the required experiment could be implemented by many ultrafast spectroscopy laboratories using pulses of tens of femtoseconds in duration. Such experiments could resolve the standing debate over the nature of coherences in photosynthetic complexes.

Allan S. Johnson; Joel Yuen-Zhou; Alán Aspuru-Guzik; Jacob J. Krich

2014-08-13T23:59:59.000Z

307

Investigation of Terahertz Vibration-Rotation Tunneling Spectra for the Water Octamer  

E-Print Network [OSTI]

Investigation of Terahertz Vibration-Rotation Tunneling Spectra for the Water Octamer Jeremy O, and Richard J. Saykally*, Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, United Kingdom Department of Chemistry, University of California, Berkeley, California 94720

Cohen, Ronald C.

308

Ratchet Effects Induced by Terahertz Radiation in Heterostructures with a Lateral Periodic Potential  

E-Print Network [OSTI]

Ratchet Effects Induced by Terahertz Radiation in Heterostructures with a Lateral Periodic of the Seebeck ratchet effect. The effect is measured in semiconductor heterostructures with a one ratchet effect, we observe a photon helicity dependent response and propose a microscopic mechanism

Ganichev, Sergey

309

A Travelling-Wave Uni-Travelling Photodiode for Continuous Wave Terahertz Generation  

E-Print Network [OSTI]

A Travelling-Wave Uni-Travelling Photodiode for Continuous Wave Terahertz Generation E. Rouvalis1 the performance of photodiodes both in terms of responsivity and frequency response. Thus, the resulting ultra-fast photodiode integrated with an antenna can be used as the photomixing element in order to generate

Haddadi, Hamed

310

Terahertz Sensor for Non-Contact Thickness and Quality Measurement of Automobile Paints of Varying Complexity  

E-Print Network [OSTI]

to resolve coating layers down to a thickness of 18 $mu{hbox{m}}$ and was validated for both single- and multi-layer automobile paint samples. Results of the terahertz measurements were benchmarked against other techniques that are currently used for non...

Su, Ke; Shen, Yao-Chun; Zeitler, J. Axel

2014-06-06T23:59:59.000Z

311

Characterization of Graphene-based Nano-antennas in the Terahertz Band  

E-Print Network [OSTI]

Characterization of Graphene-based Nano-antennas in the Terahertz Band (Invited Paper) Ignacio and Communication Technology, KTH Royal Institute of Technology, 16640 Kista, Sweden Email: lemme@kth.se Abstract--Graphene communications at the nanoscale. Indeed, graphene- based nano-antennas just a few micrometers in size have been

Politècnica de Catalunya, Universitat

312

All-electric detection of the Stokes parameters of infrared and terahertz radiation  

E-Print Network [OSTI]

All-electric detection of the Stokes parameters of infrared and terahertz radiation S.D. Ganichev to measure radiation ellipticity use polarizers-analyzers or ellipsometers. Here we report on an all-electric detection of the laser radiation polarization state describing by the Stokes parameters. The method is based

Fominov, Yakov

313

Terahertz atmospheric attenuation and continuum effects David M. Slocum,*a  

E-Print Network [OSTI]

Terahertz atmospheric attenuation and continuum effects David M. Slocum,*a Thomas M. Goyette such as pollution monitoring and detection of energetic chemicals are of particular interest. Although there has been much attention to atmospheric effects over narrow frequency windows, accurate measurements across

Massachusetts at Lowell, University of

314

Spatiotemporal shaping of half-cycle terahertz pulses by diffraction through  

E-Print Network [OSTI]

demonstrate a simple quasi-optical technique for spatiotemporal shaping of half-cycle terahertz-radiation (such as GaAs, InP, or CdTe) or radiation-damaged silicon-on-sapphire. Generated carri- ers are rapidly of finite thickness Jake Bromage, Stojan Radic, G. P. Agrawal, and C. R. Stroud, Jr. The Institute of Optics

Stroud, Carlos R.

315

Water Pentamer: Characterization of the Torsional-Puckering Manifold by Terahertz VRT Spectroscopy  

E-Print Network [OSTI]

Water Pentamer: Characterization of the Torsional-Puckering Manifold by Terahertz VRT Spectroscopy Heather A. Harker, Mark R. Viant, Frank N. Keutsch,§ Ernest A. Michael,| Ryan P. McLaughlin, and Richard J observation of this perturbation in the perdeuterated water pentamer, as well as the first observation

Cohen, Ronald C.

316

Controlling terahertz waves with meta-materials and photonic bandgap structures  

SciTech Connect (OSTI)

We will describe research conducted at Los Alamos National Laboratory towards developing components for controlling terahertz waves. We employ meta-materials and, particularly, meta-films, as very compact absorbers for controlling quasioptical beams. We believe that dielectric photonic bandgap structures could replace ordinary metal waveguide devices at THz, since metal structures become extremely lossy in this frequency range.

Shchegolkov, Dmitry [Los Alamos National Laboratory; Azad, Abul [Los Alamos National Laboratory; O' Hara, John F [Los Alamos National Laboratory; Moody, Nathan A [Los Alamos National Laboratory; Simakov, Evgenya I [Los Alamos National Laboratory

2010-12-07T23:59:59.000Z

317

A Feasibility Analysis for the Design of A Low-Cost High-Power Energy Storage System  

E-Print Network [OSTI]

A Feasibility Analysis for the Design of A Low-Cost High-Power Energy Storage System Travis Mc://www.funginstitute.berkeley.edu/sites/default/ les/EnergyStorageSystem.pdf May 3, 2014 130 Blum Hall #5580 Berkeley, CA 94720-5580 | (510) 664 of existing systems. Energy storage is a viable method for increasing the e ciency of a broad range of systems

Sekhon, Jasjeet S.

318

Research and Development of High-Power and High-Energy Electrochemical Storage Devices  

SciTech Connect (OSTI)

The accomplishments and technology progressmade during the U.S. Department of Energy (DOE) Cooperative Agreement No. DE-FC26- 05NT42403 (duration: July 11, 2005 through April 30, 2014, funded for $125 million in cost- shared research) are summarized in this Final Technical Report for a total of thirty-seven (37) collaborative programs organized by the United States Advanced Battery Consortium, LLC (USABC). The USABC is a partnership, formed in 1991, between the three U.S. domestic automakers Chrysler, Ford, and General Motors, to sponsor development of advanced high-performance batteries for electric and hybrid electric vehicle applications. The USABC provides a unique opportunity for developers to leverage their resources in combination with those of the automotive industry and the Federal government. This type of pre-competitive cooperation minimizes duplication of effort and risk of failure, and maximizes the benefits to the public of the government funds. A major goal of this program is to promote advanced battery development that can lead to commercialization within the domestic, and as appropriate, the foreign battery industry. A further goal of this program is to maintain a consortium that engages the battery manufacturers with the automobile manufacturers and other key stakeholders, universities, the National Laboratories, and manufacturers and developers that supply critical materials and components to the battery industry. Typically, the USABC defines and establishes consensus goals, conducts pre-competitive, vehicle-related research and development (R&D) in advanced battery technology. The R&D carried out by the USABC is an integral part of the DOE’s effort to develop advanced transportation technologies that will significantly improve fuel economy, comply with projected emissions and safety regulations, and use domestically produced fuels. The USABC advanced battery development plan has the following three focus areas: 1. Existing technology validation, implementation, and cost reduction. 2. Identification of the next viable technology with emphasis on the potential to meet USABC cost and operating temperature range goals. 3. Support high-risk, high-reward battery technology R&D. Specific to the Cooperative Agreement DE- FC26-05NT42403, addressing High-Energy and High Power Energy Storage Technologies, the USABC focus was on understanding and addressing the following factors (listed in priority of effort): • Cost: Reducing the current cost of lithium- ion batteries (currently about 2-3 times the FreedomCAR target ($20/kW). • Low Temperature Performance: Improving the discharge power and removing lithium plating during regenerative braking. • Calendar Life: Achieving 15-year life and getting accurate life prediction. • Abuse Tolerance: Developing a system level tolerance to overcharge, crush, and high temperature exposure. This Final Technical Report compilation is submitted in fulfillment of the subject Cooperative Agreement, and is intended to serve as a ready-reference for the outcomes of following eight categories of projects conducted by the USABC under award from the DOE’s Energy Efficiency and Renewable Energy ) Vehicle Technologies Program: USABC DoE Final Report – DoE Cooperative Agreement DE-FC26-95EE50425 8 Protected Information 1. Electric Vehicle (EV) (Section A of this report) 2. Hybrid Electric Vehicle (HEV) (Section B 3. Plug-In Hybrid Electric Vehicle (PHEV) (Section C) 4. Low-Energy Energy Storage Systems (LEESS) (Section D) 5. Technology Assessment Program (TAP) (Section E) 6. Ultracapacitors (Section F) 7. 12 Volt Start-Stop (Section G) 8. Separators (Section H) The report summarizes the main areas of activity undertaken in collaboration with the supplier community and the National Laboratories. Copies of the individual supplier final reports are available upon request. Using project gap analysis versus defined USABC goals in each area, the report documents known technology limits and provides direction on future areas of technology and performance needs for vehicle applicatio

No, author

2014-04-30T23:59:59.000Z

319

Coherent scattering from a free gas  

E-Print Network [OSTI]

We investigate decoherence in atom interferometry due to scattering from a background gas and show that the supposition that residual coherence is due to near-forward scattering is incorrect. In fact, the coherent part is ...

Sanders, Scott N.

320

System using a megawatt class millimeter wave source and a high-power rectenna to beam power to a suspended platform  

DOE Patents [OSTI]

A system for beaming power to a high altitude platform is based upon a high power millimeter gyrotron source, optical transmission components, and a high-power receiving antenna (i.e., a rectenna) capable of rectifying received millimeter energy and converting such energy into useable electrical power.

Caplan, Malcolm; Friedman, Herbert W.

2005-07-19T23:59:59.000Z

Note: This page contains sample records for the topic "high-power coherent terahertz" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

Chapter 4: Phenomenological Coherence Introduction  

E-Print Network [OSTI]

38 Chapter 4: Phenomenological Coherence Introduction The central thesis of this dissertation. In this chapter, I will highlight particular phenomenological aspects of this and other analogies. In following chapter, I will address the implications that these phenomenological properties have on cognitive

Maryland at College Park, University of

322

Terahertz inline wall thickness monitoring system for plastic pipe extrusion  

SciTech Connect (OSTI)

Conventional and commercially available inline wall thickness monitoring systems for pipe extrusion are usually based on ultrasonic or x-ray technology. Disadvantages of ultrasonic systems are the usual need of water as a coupling media and the high damping in thick walled or foamed pipes. For x-ray systems special safety requirements have to be taken into account because of the ionizing radiation. The terahertz (THz) technology offers a novel approach to solve these problems. THz waves have many properties which are suitable for the non-destructive testing of plastics. The absorption of electrical isolators is typically very low and the radiation is non-ionizing in comparison to x-rays. Through the electromagnetic origin of the THz waves they can be used for contact free measurements. Foams show a much lower absorption in contrast to acoustic waves. The developed system uses THz pulses which are generated by stimulating photoconductive switches with femtosecond laser pulses. The time of flight of THz pulses can be determined with a resolution in the magnitude of several ten femtoseconds. Hence the thickness of an object like plastic pipes can be determined with a high accuracy by measuring the time delay between two reflections on materials interfaces e.g. at the pipe's inner and outer surface, similar to the ultrasonic technique. Knowing the refractive index of the sample the absolute layer thickness from the transit time difference can be calculated easily. This method in principle also allows the measurement of multilayer systems and the characterization of foamed pipes.

Hauck, J., E-mail: j.hauck@skz.de, E-mail: d.stich@skz.de, E-mail: p.heidemeyer@skz.de, E-mail: m.bastian@skz.de, E-mail: t.hochrein@skz.de; Stich, D., E-mail: j.hauck@skz.de, E-mail: d.stich@skz.de, E-mail: p.heidemeyer@skz.de, E-mail: m.bastian@skz.de, E-mail: t.hochrein@skz.de; Heidemeyer, P., E-mail: j.hauck@skz.de, E-mail: d.stich@skz.de, E-mail: p.heidemeyer@skz.de, E-mail: m.bastian@skz.de, E-mail: t.hochrein@skz.de; Bastian, M., E-mail: j.hauck@skz.de, E-mail: d.stich@skz.de, E-mail: p.heidemeyer@skz.de, E-mail: m.bastian@skz.de, E-mail: t.hochrein@skz.de; Hochrein, T., E-mail: j.hauck@skz.de, E-mail: d.stich@skz.de, E-mail: p.heidemeyer@skz.de, E-mail: m.bastian@skz.de, E-mail: t.hochrein@skz.de [SKZ - German Plastics Center, Wuerzburg (Germany)

2014-05-15T23:59:59.000Z

323

Constructing matrices with optimal block coherence  

E-Print Network [OSTI]

Constructing matrices with optimal block coherence Andrew Thompson (Duke University) Joint work · Background: · The subspace packing problem · An equivalent notion: block coherence · Who is interested in this? #12;Outline · Background: · The subspace packing problem · An equivalent notion: block coherence

Thompson, Andrew

324

Quantizations on the circle and coherent states  

E-Print Network [OSTI]

We present a possible construction of coherent states on the unit circle as configuration space. Our approach is based on Borel quantizations on S^1 including the Aharonov-Bohm type quantum description. The coherent states are constructed by Perelomov's method as group related coherent states generated by Weyl operators on the quantum phase space Z x S^1. Because of the duality of canonical coordinates and momenta, i.e. the angular variable and the integers, this formulation can also be interpreted as coherent states over an infinite periodic chain. For the construction we use the analogy with our quantization and coherent states over a finite periodic chain where the quantum phase space was Z_M x Z_M. The coherent states constructed in this work are shown to satisfy the resolution of unity. To compare them with canonical coherent states, also some of their further properties are studied demonstrating similarities as well as substantial differences.

Chadzitaskos, G; Tolar, J

2012-01-01T23:59:59.000Z

325

Coherent Phase Argument for Inflation  

E-Print Network [OSTI]

Cosmologists have developed a phenomenally successful picture of structure in the universe based on the idea that the universe expanded exponentially in its earliest moments. There are three pieces of evidence for this exponential expansion -- {\\it inflation} -- from observations of anisotropies in the cosmic microwave background. First, the shape of the primordial spectrum is very similar to that predicted by generic inflation models. Second, the angular scale at which the first acoustic peak appears is consistent with the flat universe predicted by inflation. Here I describe the third piece of evidence, perhaps the most convincing of all: the phase coherence needed to account for the clear peak/trough structure observed by the WMAP satellite and its predecessors. I also discuss alternatives to inflation that have been proposed recently and explain how they produce coherent phases.

Scott Dodelson

2003-09-05T23:59:59.000Z

326

Evaporation-assisted high-power impulse magnetron sputtering: The deposition of tungsten oxide as a case study  

SciTech Connect (OSTI)

The deposition rate during the synthesis of tungsten trioxide thin films by reactive high-power impulse magnetron sputtering (HiPIMS) of a tungsten target increases, above the dc threshold, as a result of the appropriate combination of the target voltage, the pulse duration, and the amount of oxygen in the reactive atmosphere. This behavior is likely to be caused by the evaporation of the low melting point tungsten trioxide layer covering the metallic target in such working conditions. The HiPIMS process is therefore assisted by thermal evaporation of the target material.

Hemberg, Axel; Dauchot, Jean-Pierre; Snyders, Rony; Konstantinidis, Stephanos [Materia Nova Research Center-Parc Initialis, 1, Avenue Copernic, B-7000 Mons, Belgium and Chimie des Interactions Plasma-Surface, CIRMAP, Universite de Mons-20, Place du Parc, B-7000 Mons (Belgium); Chimie des Interactions Plasma-Surface, CIRMAP, Universite de Mons-20, Place du Parc, B-7000 Mons (Belgium); Materia Nova Research Center-Parc Initialis, 1, Avenue Copernic, B-7000 Mons (Belgium) and Chimie des Interactions Plasma-Surface, CIRMAP, Universite de Mons-20, Place du Parc, B-7000 Mons (Belgium); Chimie des Interactions Plasma-Surface, CIRMAP, Universite de Mons-20, Place du Parc, B-7000 Mons (Belgium)

2012-07-15T23:59:59.000Z

327

Characterization of plasma expansion dynamics in a high power diode with a carbon-fiber-aluminum cathode  

SciTech Connect (OSTI)

Thermal plasma expansion is characterised during the operation of a high power diode with an explosive emission carbon-fiber-aluminum cathode driven by a 250?kV, 150?ns accelerating pulse. It is found that a quasi-stationary state of plasma expansion is obtained during the main part of the accelerating pulse and the whole plasma expansion exhibits an “U”-shape velocity evolution. A theoretical model describing the dynamics of plasma expansion is developed, which indicates that the plasma expansion velocity is determined by equilibrium between the diode current density and plasma thermal electron current density.

Ju, J.-C., E-mail: jujinchuan@126.com [College of Optoelectronic Science and Engineering, National University of Defense Technology, Changsha 410073 (China); Laboratoire de Physique des Gaz et des Plasmas, CNRS-Université Paris-Sud, Orsay 91405 (France); Liu, L.; Cai, D. [College of Optoelectronic Science and Engineering, National University of Defense Technology, Changsha 410073 (China)

2014-06-09T23:59:59.000Z

328

Emission of terahertz waves from stacks of intrinsic Josephson junctions.  

SciTech Connect (OSTI)

By patterning mesoscopic crystals of Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8} (BSCCO) into electromagnetic resonators the oscillations of a large number of intrinsic Josephson junctions can be synchronized into a macroscopic coherent state accompanied by the emission of strong continuous wave THz-radiation. The temperature dependence of the emission is governed by the interplay of self-heating in the resonator and by re-trapping of intrinsic Josephson junctions which can yield a strongly non-monotonic temperature dependence of the emission power. Furthermore, proper shaping of the resonators yields THz-sources with voltage-tunable emission frequencies.

Gray, K. E.; Koshelev, A. E.; Kurter, C.; Kadowaki, K.; Yamamoto, T.; Minami, H.; Yamaguchi, H.; Tachiki, M.; Kwok, W.-K.; Welp, U.; Materials Science Division; Izmir Inst. of Tech.; Univ. Tsukuba; Univ. Tokyo

2009-06-01T23:59:59.000Z

329

Preparation of room temperature terahertz detector with lithium tantalate crystal and thin film  

SciTech Connect (OSTI)

Research on room temperature terahertz (THz) detector is essential for promoting the application of THz science and technology. Both lithium tantalate crystal (LiTaO{sub 3}) and lithium tantalate thin film were used to fabricate the THz detector in this paper. Polishing process were used to reduce the thickness of LiTaO{sub 3} crystal slice by chemical mechanical polishing techniques and an improved sol-gel process was used to obtain high concentration LiTaO{sub 3} precursor solution to fabricate LiTaO{sub 3} thin film. Three dimension models of two THz detectors were set up and the temperature increasing map of two devices were simulated using finite element method. The lowest noise equivalent power value for terahertz detector using pyroelectric material reaches 6.8 × 10{sup ?9} W at 30 Hz operating frequency, which is suitable for THz imaging application.

Wang, Jun, E-mail: ueoewj@gmail.com; Gou, Jun; Li, Weizhi [State Key Lab of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, University of Electronic Science and Technology of China, Chengdu 610054 (China)] [State Key Lab of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, University of Electronic Science and Technology of China, Chengdu 610054 (China)

2014-02-15T23:59:59.000Z

330

Ultrafast terahertz-induced response of GeSbTe phase-change materials  

SciTech Connect (OSTI)

The time-resolved ultrafast electric field-driven response of crystalline and amorphous GeSbTe films has been measured all-optically, pumping with single-cycle terahertz pulses as a means of biasing phase-change materials on a sub-picosecond time-scale. Utilizing the near-band-gap transmission as a probe of the electronic and structural response below the switching threshold, we observe a field-induced heating of the carrier system and resolve the picosecond-time-scale energy relaxation processes and their dependence on the sample annealing condition in the crystalline phase. In the amorphous phase, an instantaneous electroabsorption response is observed, quadratic in the terahertz field, followed by field-driven lattice heating, with Ohmic behavior up to 200?kV/cm.

Shu, Michael J. [Department of Applied Physics, Stanford University, Stanford, California 94305 (United States); Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Zalden, Peter [Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Chen, Frank [Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Department of Electrical Engineering, Stanford University, Stanford, California 94305 (United States); Weems, Ben [Department of Materials Science and Engineering, Stanford University, Stanford, California 94305 (United States); Chatzakis, Ioannis [Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Xiong, Feng; Jeyasingh, Rakesh; Pop, Eric; Philip Wong, H.-S. [Department of Electrical Engineering, Stanford University, Stanford, California 94305 (United States); Hoffmann, Matthias C. [SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Wuttig, Matthias [I. Physikalisches Institut, RWTH Aachen University, 52056 Aachen (Germany); JARA–Fundamentals of Information Technology, RWTH Aachen University, 52056 Aachen (Germany); Lindenberg, Aaron M., E-mail: aaronl@stanford.edu [Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Department of Materials Science and Engineering, Stanford University, Stanford, California 94305 (United States)

2014-06-23T23:59:59.000Z

331

Thermal tunability in terahertz metamaterials fabricated on strontium titanate single crystal substrates  

E-Print Network [OSTI]

We report an experimental demonstration of thermal tuning of resonance frequency in a planar terahertz metamaterial consisting of a gold split-ring resonator array fabricated on a bulk single crystal strontium titanate (SrTiO3) substrate. Cooling the metamaterial starting from 409 K down to 150 K causes about 50% shift in resonance frequency as compare to its room temperature resonance, and there is very little variation in resonance strength. The resonance shift is due to the temperature-dependent refractive index (or the dielectric constant) of the strontium titanate. The experiment opens up avenues for designing tunable terahertz devices by exploiting the temperature sensitive characteristic of high dielectric constant substrates and complex metal oxide materials.

Singh, Ranjan; Jia, Q X; Taylor, Antoinette J; Chen, Hou-Tong

2011-01-01T23:59:59.000Z

332

Terahertz and infrared transmission of an organic/inorganic hybrid thermoelectric material  

SciTech Connect (OSTI)

We report terahertz and infrared transmission measurements of a high-performance thermoelectric material containing tellurium nanowires in a conducting polymer poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) matrix. The DC electrical conductivity of the hybrid material (41?S/cm) is approximately one hundred times that of pure PEDOT:PSS and more than 400 times that of a film of pure tellurium nanowires, while the terahertz-frequency (THz) conductivity of PEDOT:PSS and the hybrid material are comparable at f???2THz. A frequency-dependent conductivity model indicates that the increased DC conductivity of the hybrid material results from an increase in the DC charge mobility rather than in the free charge density. We suggest that the increased DC conductivity of the hybrid material results from an increase in linkage between PEDOT domains by the tellurium nanowires.

Heyman, J. N., E-mail: heyman@macalester.edu; Alebachew, B. A.; Kaminski, Z. S.; Nguyen, M. D. [Physics Department, Macalester College, St. Paul, Minnesota 55105 (United States); Coates, N. E.; Urban, J. J. [The Molecular Foundry, Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

2014-04-07T23:59:59.000Z

333

Theory of terahertz/near-infrared optical mixing in quantum wells in strong magnetic fields Takeshi Inoshita, Junichiro Kono,* and Hiroyuki Sakaki  

E-Print Network [OSTI]

Theory of terahertz/near-infrared optical mixing in quantum wells in strong magnetic fields TakeshiAs quantum wells illuminated simultaneously by near-infrared and terahertz THz radiation in strong magnetic the sample is illuminated simul- taneously by THz frequency T) and near-infrared fre- quency N) radiation

Kono, Junichiro

334

GaSb homojunctions for far-infrared ,,terahertz... detection P. V. V. Jayaweera, S. G. Matsik, and A. G. U. Pereraa  

E-Print Network [OSTI]

terahertz imaging as a method of screening passengers for explosives at air- ports. For military for the surging demand of high performance terahertz detectors in recent years. Charge transport properties3 the photoexcited carriers with energy h larger than the band-edge offset between the doped emit- ter layer

Perera, A. G. Unil

335

Fundamental Studies and Development of III-N Visible LEDs for High-Power Solid-State Lighting Applications  

SciTech Connect (OSTI)

The goal of this program is to understand in a fundamental way the impact of strain, defects, polarization, and Stokes loss in relation to unique device structures upon the internal quantum efficiency (IQE) and efficiency droop (ED) of III-nitride (III-N) light-emitting diodes (LEDs) and to employ this understanding in the design and growth of high-efficiency LEDs capable of highly-reliable, high-current, high-power operation. This knowledge will be the basis for our advanced device epitaxial designs that lead to improved device performance. The primary approach we will employ is to exploit new scientific and engineering knowledge generated through the application of a set of unique advanced growth and characterization tools to develop new concepts in strain-, polarization-, and carrier dynamics-engineered and low-defect materials and device designs having reduced dislocations and improved carrier collection followed by efficient photon generation. We studied the effects of crystalline defect, polarizations, hole transport, electron-spillover, electron blocking layer, underlying layer below the multiplequantum- well active region, and developed high-efficiency and efficiency-droop-mitigated blue LEDs with a new LED epitaxial structures. We believe new LEDs developed in this program will make a breakthrough in the development of high-efficiency high-power visible III-N LEDs from violet to green spectral region.

Dupuis, Russell

2012-02-29T23:59:59.000Z

336

Mechanism of terahertz photoconductivity in semimetallic HgTe/CdHgTe quantum wells  

SciTech Connect (OSTI)

Terahertz photoconductivity in magnetic fields in semimetallic HgTe/CdHgTe quantum wells has been studied. The main contribution to photoconductivity comes from a signal that appears as a result of electron-gas heating. It is shown that, with the cyclotron resonance conditions satisfied, the photoconductivity signal is composed of cyclotron-resonance and bolometric components. However, in this case too, the bolometric contribution predominates.

Vasilyev, Yu. B., E-mail: yu.vasilyev@mail.ioffe.ru [Russian Academy of Sciences, Ioffe Physical-Technical Institute (Russian Federation); Mikhailov, N. N. [Russian Academy of Sciences, Rzhanov Institute of Semiconductor Physics, Siberian Branch (Russian Federation); Gouider, F. [Institut fuer Angewandte Physik (Germany); Vasilyeva, G. Yu. [St. Petersburg State Polytechnic University (Russian Federation); Nachtwei, G. [Institut fuer Angewandte Physik (Germany)

2012-05-15T23:59:59.000Z

337

Does coherence enhance transport in photosynthesis?  

E-Print Network [OSTI]

Recent observations of coherence in photosynthetic complexes have led to the question of whether quantum effects can occur in vivo, not under femtosecond laser pulses but in incoherent sunlight and at steady state, and, if so, whether the coherence explains the high exciton transfer efficiency. We distinguish several types of coherence and show that although some photosynthetic pathways are partially coherent processes, photosynthesis in nature proceeds through stationary states. This distinction allows us to rule out several mechanisms of transport enhancement in sunlight. In particular, although they are crucial for understanding exciton transport, neither wavelike motion nor microscopic coherence, on their own, enhance the efficiency. By contrast, two partially coherent mechanisms---ENAQT and supertransfer---can enhance transport even in sunlight and thus constitute motifs for the optimisation of artificial sunlight harvesting. Finally, we clarify the importance of ultrafast spectroscopy in understanding incoherent processes.

Ivan Kassal; Joel Yuen-Zhou; Saleh Rahimi-Keshari

2012-10-18T23:59:59.000Z

338

Does coherence enhance transport in photosynthesis?  

E-Print Network [OSTI]

Recent observations of coherence in photosynthetic complexes have led to the question of whether quantum effects can occur in vivo, not under femtosecond laser pulses but in incoherent sunlight and at steady state, and, if so, whether the coherence explains the high exciton transfer efficiency. We distinguish several types of coherence and show that although some photosynthetic pathways are partially coherent processes, photosynthesis in nature proceeds through stationary states. This distinction allows us to rule out several mechanisms of transport enhancement in sunlight. In particular, although they are crucial for understanding exciton transport, neither wavelike motion nor microscopic coherence, on their own, enhance the efficiency. By contrast, two partially coherent mechanisms---ENAQT and supertransfer---can enhance transport even in sunlight and thus constitute motifs for the optimisation of artificial sunlight harvesting. Finally, we clarify the importance of ultrafast spectroscopy in understanding i...

Kassal, Ivan; Rahimi-Keshari, Saleh

2012-01-01T23:59:59.000Z

339

Decoherence of multimode thermal squeezed coherent states  

SciTech Connect (OSTI)

It is well known that any multimode positive definite quadratic Hamiltonian can be transformed into a hamiltonian of uncoupled harmonic oscillators. Based on this theorem, the multimode thermal squeezed coherent states are constructed in terms of density operators. Decoherence of multimode thermal squeezed coherent states in investigated via the characteristic function and it is shown that the decohered (reduced) states are still thermal squeezed coherent states in general.

Yeh, L.

1992-08-14T23:59:59.000Z

340

Coherence delay augmented laser beam homogenizer  

DOE Patents [OSTI]

The geometrical restrictions on a laser beam homogenizer are relaxed by ug a coherence delay line to separate a coherent input beam into several components each having a path length difference equal to a multiple of the coherence length with respect to the other components. The components recombine incoherently at the output of the homogenizer, and the resultant beam has a more uniform spatial intensity suitable for microlithography and laser pantogography. Also disclosed is a variable aperture homogenizer, and a liquid filled homogenizer.

Rasmussen, P.; Bernhardt, A.

1993-06-29T23:59:59.000Z

Note: This page contains sample records for the topic "high-power coherent terahertz" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
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We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

Coherence delay augmented laser beam homogenizer  

DOE Patents [OSTI]

The geometrical restrictions on a laser beam homogenizer are relaxed by ug a coherence delay line to separate a coherent input beam into several components each having a path length difference equal to a multiple of the coherence length with respect to the other components. The components recombine incoherently at the output of the homogenizer, and the resultant beam has a more uniform spatial intensity suitable for microlithography and laser pantogography. Also disclosed is a variable aperture homogenizer, and a liquid filled homogenizer.

Rasmussen, Paul (Livermore, CA); Bernhardt, Anthony (Berkeley, CA)

1993-01-01T23:59:59.000Z

342

Coherent states for the nonlinear harmonic oscillator  

SciTech Connect (OSTI)

Wave packets for the quantum nonlinear oscillator are considered in the generalized coherent state framework. To first order in the nonlinearity parameter the coherent state behaves very similar to its classical counterpart. The position expectation value oscillates in a simple harmonic manner. The energy-momentum uncertainty relation is time independent as in a harmonic oscillator. Various features (such as the squeezed state nature) of the coherent state have been discussed.

Ghosh, Subir [Physics and Applied Mathematics Unit, Indian Statistical Institute, 203 B. T. Road, Kolkata 700108 (India)

2012-06-15T23:59:59.000Z

343

Optimization Online - On the Coherent Risk Measure ...  

E-Print Network [OSTI]

Nov 25, 2014 ... Abstract: We give a complete characterization of both comonotone and not comonotone coherent risk measures in the discrete finite probability ...

KEREM UGURLU

2014-11-25T23:59:59.000Z

344

Coherent Control of Quantum Matter  

SciTech Connect (OSTI)

This talk addresses some recent work aimed at controlling the low-lying electrodynamics of quantum solids using strong field transients. The excitation of selected vibrational resonances to manipulate the many-body physics of one dimensional Mott Hubbard Insulators and to perturb competing orders in High-Tc superconductors is also covered. Finally, the speaker shows how the electrodynamics of layered superconductors can be driven through the orderparameter phase gradient, demonstrating ultrafast transistor action in a layered superconductor. Advances in the use of coherent optics, from tabletop sources to THz and x-ray free-electron lasers are also discussed.

Cavalleri, Andrea (Max Planck Institute) [Max Planck Institute

2011-10-05T23:59:59.000Z

345

Coherent instabilities in random lasers  

SciTech Connect (OSTI)

A numerical study is presented of random lasers as a function of the pumping rate above the threshold for lasing. Depending on the leakiness of the system resonances, which is typically larger in random lasers compared to conventional lasers, we observe that the stationary lasing regime becomes unstable above a second threshold. Coherent instabilities are observed as self pulsation at a single frequency of the output intensity, population inversion, as well as the atomic polarization. We find these Rabi oscillations have the same frequency everywhere in the random laser despite the fact that the field intensity strongly depends on the spatial location.

Andreasen, Jonathan; Sebbah, Patrick; Vanneste, Christian [Laboratoire de Physique de la Matiere Condensee, CNRS UMR 6622, Universite de Nice-Sophia Antipolis, Parc Valrose, F-06108, Nice Cedex 02 (France)

2011-08-15T23:59:59.000Z

346

DEPOSITION OF NIOBIUM AND OTHER SUPERCONDUCTING MATERIALS WITH HIGH POWER IMPULSE MAGNETRON SPUTTERING: CONCEPT AND FIRST RESULTS  

SciTech Connect (OSTI)

Niobium coatings on copper cavities have been considered as a cost-efficient replacement of bulk niobium RF cavities, however, coatings made by magnetron sputtering have not quite lived up to high expectations due to Q-slope and other issues. High power impulse magnetron sputtering (HIPIMS) is a promising emerging coatings technology which combines magnetron sputtering with a pulsed power approach. The magnetron is turned into a metal plasma source by using very high peak power density of ~ 1 kW/cm{sup 2}. In this contribution, the cavity coatings concept with HIPIMS is explained. A system with two cylindrical, movable magnetrons was set up with custom magnetrons small enough to be inserted into 1.3 GHz cavities. Preliminary data on niobium HIPIMS plasma and the resulting coatings are presented. The HIPIMS approach has the potential to be extended to film systems beyond niobium, including other superconducting materials and/or multilayer systems.

High Current Electronics Institute, Tomsk, Russia; Anders, Andre; Mendelsberg, Rueben J.; Lim, Sunnie; Mentink, Matthijs; Slack, Jonathan L.; Wallig, Joseph G.; Nollau, Alexander V.; Yushkov, Georgy Yu.

2011-07-24T23:59:59.000Z

347

Numerical simulations of output pulse extraction from a high-power microwave compressor with a plasma switch  

SciTech Connect (OSTI)

Numerical simulations of the process of electromagnetic energy release from a high-power microwave pulse compressor comprising a gas-filled cavity and interference switch were carried out. A microwave plasma discharge in a rectangular waveguide H-plane tee was modeled with the use of the fully electromagnetic particle-in-cell code MAGIC. The gas ionization, plasma evolution, and interaction with RF fields accumulated within the compressor were simulated using different approaches provided by the MAGIC code: particle-in-cell approach accounting for electron-neutral collisions, gas conductivity model based on the concept of mobility, and hybrid modeling. The dependences of the microwave output pulse peak power and waveform on parameters that can be controlled in experiments, such as an external ionization rate, RF field amplitude, and background gas pressure, were investigated.

Shlapakovski, Anatoli; Beilin, Leonid; Bliokh, Yuri; Donskoy, Moshe; Krasik, Yakov E. [Physics Department, Technion, Haifa 32000 (Israel); Hadas, Yoav [Department of Applied Physics, Rafael, PO Box 2250, Haifa 31021 (Israel); Schamiloglu, Edl [Department of Electrical and Computer Engineering, University of New Mexico, Albuquerque, New Mexico 87131 (United States)

2014-05-07T23:59:59.000Z

348

High damage-resistant Mo mirror for high-power TEA CO/sub 2/ laser systems  

SciTech Connect (OSTI)

A high-purity molybdenum (Mo) mirror was developed by an electron-beam melting method (e.b.m. Mo mirror). For high-power TEA CO/sub 2/ laser, the e.b.m. Mo mirror has two to four times higher surface damage threshold than that of an Au-coated glass mirror and three times longer lifetime than that of a powder metallurgy Mo mirror (p.m. Mo mirror) when laser energy density lower than 60 J/cm/sup 2/ was irradiated with a 0.5-pps repetition rate. It was found that the difference between the e.b.m. Mo mirror and the p.m. Mo mirror at the laser-damage threshold was due to the five surface without voids and the small amount of impurities.

Ichikawa, Y.; Yoshida, K.; Tsunawaki, Y.; Yamanaka, M.; Yamanaka, T.; Yamanaka, C.; Okamoto, H.; Matsusue, N.; Kitajima, K.

1987-09-01T23:59:59.000Z

349

2012 ARPA-E Energy Innovation Summit: Profiling Foro Energy: High Power Lasers - Long Distances (Performer Video)  

ScienceCinema (OSTI)

The third annual ARPA-E Energy Innovation Summit was held in Washington D.C. in February, 2012. The event brought together key players from across the energy ecosystem - researchers, entrepreneurs, investors, corporate executives, and government officials - to share ideas for developing and deploying the next generation of energy technologies. A few videos were selected for showing during the Summit to attendees. These 'performer videos' highlight innovative research that is ongoing and related to the main topics of the Summit's sessions. Featured in this video from Foro Energy are Joel Moxley, Founder and CEO, Mark Zediker, Founder and CTO, and Paul Deutch, President and COO. Steven Chu, Secretary of Energy, also appears briefly in this video to praise the accomplishment of a high powered laser that can transmit that power long distances for faster and more powerful drilling of geothermal, oil, and gas wells.

None Available

2012-03-21T23:59:59.000Z

350

2012 ARPA-E Energy Innovation Summit: Profiling Foro Energy: High Power Lasers - Long Distances (Performer Video)  

SciTech Connect (OSTI)

The third annual ARPA-E Energy Innovation Summit was held in Washington D.C. in February, 2012. The event brought together key players from across the energy ecosystem - researchers, entrepreneurs, investors, corporate executives, and government officials - to share ideas for developing and deploying the next generation of energy technologies. A few videos were selected for showing during the Summit to attendees. These 'performer videos' highlight innovative research that is ongoing and related to the main topics of the Summit's sessions. Featured in this video from Foro Energy are Joel Moxley, Founder and CEO, Mark Zediker, Founder and CTO, and Paul Deutch, President and COO. Steven Chu, Secretary of Energy, also appears briefly in this video to praise the accomplishment of a high powered laser that can transmit that power long distances for faster and more powerful drilling of geothermal, oil, and gas wells.

None Available

2012-02-28T23:59:59.000Z

351

High power impulse magnetron sputtering and related discharges: scalable plasma sources for plasma-based ion implantation and deposition  

SciTech Connect (OSTI)

High power impulse magnetron sputtering (HIPIMS) and related self-sputtering techniques are reviewed from a viewpoint of plasma-based ion implantation and deposition (PBII&D). HIPIMS combines the classical, scalable sputtering technology with pulsed power, which is an elegant way of ionizing the sputtered atoms. Related approaches, such as sustained self-sputtering, are also considered. The resulting intense flux of ions to the substrate consists of a mixture of metal and gas ions when using a process gas, or of metal ions only when using `gasless? or pure self-sputtering. In many respects, processing with HIPIMS plasmas is similar to processing with filtered cathodic arc plasmas, though the former is easier to scale to large areas. Both ion implantation and etching (high bias voltage, without deposition) and thin film deposition (low bias, or bias of low duty cycle) have been demonstrated.

Anders, Andre

2009-09-01T23:59:59.000Z

352

Optical coherence domain reflectometry guidewire  

DOE Patents [OSTI]

A guidewire with optical sensing capabilities is based on a multiplexed optical coherence domain reflectometer (OCDR), which allows it to sense location, thickness, and structure of the arterial walls or other intra-cavity regions as it travels through the body during minimally invasive medical procedures. This information will be used both to direct the guidewire through the body by detecting vascular junctions and to evaluate the nearby tissue. The guidewire contains multiple optical fibers which couple light from the proximal to distal end. Light from the fibers at the distal end of the guidewire is directed onto interior cavity walls via small diameter optics such as gradient index lenses and mirrored corner cubes. Both forward viewing and side viewing fibers can be included. The light reflected or scattered from the cavity walls is then collected by the fibers, which are multiplexed at the proximal end to the sample arm of an optical low coherence reflectometer. The guidewire can also be used in nonmedical applications.

Colston, Billy W. (Livermore, CA); Everett, Matthew (Pleasanton, CA); Da Silva, Luiz B. (Danville, CA); Matthews, Dennis (Moss Beach, CA)

2001-01-01T23:59:59.000Z

353

A self-consistent regime of generation of terahertz radiation by an optical pulse with a tilted intensity front  

SciTech Connect (OSTI)

We derived a self-consistent system of nonlinear wave equations describing the terahertz generation in dielectric uniaxial crystals by optical pulsed radiation with a tilted wavefront. The numerical analysis of the system of equations showed that the generation of a broadband one-period terahertz signal is accompanied by a red shift of the carrier frequency of the optical pulse, the magnitude of the shift being proportional to the pulse intensity. The generation efficiency with respect to energy reached a maximum at a certain distance of propagation in the crystal, after which the efficiency decreased. A satisfactory agreement was obtained between theoretical calculations and experimental data of other investigations. (generation of terahertz radiation)

Bugai, A N; Sazonov, S V; Shashkov, Andrei Yu

2012-11-30T23:59:59.000Z

354

Coherence in natural language : data structures and applications  

E-Print Network [OSTI]

(cont.) baseline, and that some coherence-based approaches best predict the human data. However, coherence-based algorithms that operate on trees did not perform as well as coherence-based algorithms that operate on more ...

Wolf, Florian, 1975-

2005-01-01T23:59:59.000Z

355

Can Natural Sunlight Induce Coherent Exciton Dynamics?  

E-Print Network [OSTI]

Excitation of a model photosynthetic molecular aggregate by incoherent sunlight is systematically examined. For a closed system, the excited state coherence induced by the sunlight oscillates with an average amplitude that is inversely proportional to the excitonic gap, and reaches a stationary amplitude that depends on the temperature and coherence time of the radiation field. For an open system, the light-induced dynamical coherence relaxes to a static coherence determined by the non-canonical thermal distribution resulting from the entanglement with the phonon bath. The decay of the excited state population to the common ground state establishes a non-equilibrium steady-state flux driven by the sunlight, and it defines a time window to observe the transition from dynamical to static coherence. For the parameters relevant to photosynthetic systems, the exciton dynamics initiated by the sunlight exhibits a non-negligible amount of dynamical coherence (quantum beats) on the sub-picosecond timescale; however, this sub-picosecond time-scale is long enough for light-harvesting systems to establish static coherence, which plays a crucial role in efficient energy transfer. Further, a relationship is established between the non-equilibrium steady-state induced by the sunlight and the coherent dynamics initiated from the ground state by a laser $\\delta$-pulse, thereby making a direct connection between incoherent sunlight excitation and ultrafast spectroscopy.

Jan Olšina; Arend G. Dijkstra; Chen Wang; Jianshu Cao

2014-08-21T23:59:59.000Z

356

Tunable coherent radiation at soft X-ray wavelengths: Generation and interferometric applications  

SciTech Connect (OSTI)

The availability of high power, spectrally and spatially coherent soft x-rays (SXR) would facilitate a wide variety of experiments as this energy region covers the primary resonances of many magnetic and biological materials. Specifically, there are the carbon and oxygen K-edges that are critical for biological imaging in the water window and the L-edges of iron, nickel, and cobalt for which imaging and scattering studies can be performed. A new coherent soft X-ray branchline at the Advanced Light Source has begun operation (beamline 12.0.2). Using the third harmonic from an 8 cm period undulator, this branch delivers coherent soft x-rays with photon energies ranging from 200eV to 1keV. This branchline is composed of two sub-branches one at 14X demagnification and the other 8X demagnification. The former is optimized for use at 500eV and the latter at 800eV. Here the expected power from the third harmonic of this undulator and the beamline design and characterization is presented. The characterization includes measurements on available photon flux as well as a series of double pinhole experiments to determine the coherence factor with respect to transverse distance. The first high quality Airy patterns at SXR wavelengths are created with this new beamline. The operation of this new beamline allows for interferometry to be performed in the SXR region. Here an interferometric experiment designed to directly determine the index of refraction of a material under test is performed. Measurements are first made in the EUV region using an established beamline (beamline12.0.1) to measure silicon, ruthenium and tantalum silicon nitride. This work is then extended to the SXR region using beamline 12.0.2 to test chromium and vanadium.

Rosfjord, Kristine Marie

2004-07-01T23:59:59.000Z

357

The Fidelity and Trace Norm Distances for Quantifying Coherence  

E-Print Network [OSTI]

We investigate the coherence measures induced by fidelity and trace norm, based on the recent proposed coherence quantification in [Phys. Rev. Lett. 113, 140401, 2014]. We show that the fidelity of coherence does not in general satisfy the monotonicity requirement as a measure of coherence under the subselection of measurements condition. We find that the trace norm of coherence can act as a measure of coherence for qubit case and some special class of qutrits.

Lian-He Shao; Zhengjun Xi; Heng Fan; Yongming Li

2014-10-30T23:59:59.000Z

358

Coherent Quantum Dynamics: What Fluctuations Can Tell  

E-Print Network [OSTI]

Coherent states provide a natural connection of quantum systems to their classical limit and are employed in various fields of physics. Here we derive general systematic expansions, with respect to quantum parameters, of expectation values of products of arbitrary operators within both oscillator coherent states and SU(2) coherent states. In particular, we generally prove that the energy fluctuations of an arbitrary Hamiltonian are in leading order entirely due to the time dependence of the classical variables. These results add to the list of wellknown properties of coherent states and are applied here to the Lipkin-Meshkov-Glick model, the Dicke model, and to coherent intertwiners in spin networks as considered in Loop Quantum Gravity.

Schliemann, John

2015-01-01T23:59:59.000Z

359

Numerical and simulation study of terahertz radiation generation by laser pulses propagating in the extraordinary mode in magnetized plasma  

SciTech Connect (OSTI)

A one-dimensional numerical model for studying terahertz radiation generation by intense laser pulses propagating, in the extraordinary mode, through magnetized plasma has been presented. The direction of the static external magnetic field is perpendicular to the polarization as well as propagation direction of the laser pulse. A transverse electromagnetic wave with frequency in the terahertz range is generated due to the presence of the magnetic field. Further, two-dimensional simulations using XOOPIC code show that the THz fields generated in plasma are transmitted into vacuum. The fields obtained via simulation study are found to be compatible with those obtained from the numerical model.

Jha, Pallavi; Kumar Verma, Nirmal [Department of Physics, University of Lucknow, Lucknow-226007 (India)

2014-06-15T23:59:59.000Z

360

aligning coherent bremsstrahlung: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

internal state of the plant. Importantly, coherent observers avoid measurements of the plant outputs. We compare our coherent observers with a classical (measurement-based)...

Note: This page contains sample records for the topic "high-power coherent terahertz" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

Efficient terahertz wave generation from GaP crystals pumped by chirp-controlled pulses from femtosecond photonic crystal fiber amplifier  

SciTech Connect (OSTI)

A chirp-tunable femtosecond 10?W, 42?MHz photonic-crystal-fiber oscillator-amplifier system that is capable of delivering sub-60 fs light pulses at 1040?nm is used to demonstrate high-efficiency terahertz radiation generation via optical rectification in GaP crystals only a few millimeters in length. The optimization of the chirp of the fiber-laser pulses is shown to radically enhance the terahertz output, indicating one possible way to more efficiently use these extended nonlinear crystals in compact fiber-pumped terahertz radiation sources.

Li, Jiang; Shi, Junkai; Xu, Baozhong; Xing, Qirong; Wang, Chingyue [Ultrafast Laser Laboratory, College of Precision Instrument and Optoelectronics Engineering, Key Laboratory of Optoelectronic Information Technology (Ministry of Education), Tianjin University, Tianjin 300072 (China); Chai, Lu, E-mail: lu-chai@tju.edu.cn, E-mail: yanfengli@tju.edu.cn; Liu, Bowen; Hu, Minglie; Li, Yanfeng, E-mail: lu-chai@tju.edu.cn, E-mail: yanfengli@tju.edu.cn [Ultrafast Laser Laboratory, College of Precision Instrument and Optoelectronics Engineering, Key Laboratory of Optoelectronic Information Technology (Ministry of Education), Tianjin University, Tianjin 300072 (China); MOEMS Key Laboratory (Ministry of Education), Tianjin University, Tianjin 300072 (China); Fedotov, Andrey B. [Physics Department, Russian Quantum Center, International Laser Center, M.V. Lomonosov Moscow State University, Moscow 119992 (Russian Federation); Zheltikov, Aleksei M. [Physics Department, Russian Quantum Center, International Laser Center, M.V. Lomonosov Moscow State University, Moscow 119992 (Russian Federation); Department of Physics and Astronomy, Texas A and M University, College Station, Texas 77843 (United States)

2014-01-20T23:59:59.000Z

362

Quantum Coherence Arguments for Cosmological Scale  

SciTech Connect (OSTI)

Homogeneity and correlations in the observed CMB are indicative of some form of cosmological coherence in early times. Quantum coherence in the early universe would be expected to give space-like phase coherence to any effects sourced to those times. If dark energy de-coherence is assumed to occur when the rate of expansion of the relevant cosmological scale parameter in the Friedmann-Lemaitre equations is no longer supra-luminal, a critical energy density is immediately defined. It is shown that the general class of dynamical models so defined necessarily requires a spatially flat cosmology in order to be consistent with observed structure formation. The basic assumption is that the dark energy density which is fixed during de-coherence is to be identified with the cosmological constant. It is shown for the entire class of models that the expected amplitude of fluctuations driven by the dark energy de-coherence process is of the order needed to evolve into the fluctuations observed in cosmic microwave background radiation and galactic clustering. The densities involved during de-coherence which correspond to the measured dark energy density turn out to be of the electroweak symmetry restoration scale. In an inflationary cosmology, this choice of the scale parameter in the FL equations directly relates the scale of dark energy decoherence to the De Sitter scales (associated with the positive cosmological constants) at both early and late times.

Lindesay, James; /SLAC

2005-05-27T23:59:59.000Z

363

Invited Article: An integrated mid-infrared, far-infrared, and terahertz optical Hall effect instrument  

SciTech Connect (OSTI)

We report on the development of the first integrated mid-infrared, far-infrared, and terahertz optical Hall effect instrument, covering an ultra wide spectral range from 3 cm{sup ?1} to 7000 cm{sup ?1} (0.1–210 THz or 0.4–870 meV). The instrument comprises four sub-systems, where the magneto-cryostat-transfer sub-system enables the usage of the magneto-cryostat sub-system with the mid-infrared ellipsometer sub-system, and the far-infrared/terahertz ellipsometer sub-system. Both ellipsometer sub-systems can be used as variable angle-of-incidence spectroscopic ellipsometers in reflection or transmission mode, and are equipped with multiple light sources and detectors. The ellipsometer sub-systems are operated in polarizer-sample-rotating-analyzer configuration granting access to the upper left 3 × 3 block of the normalized 4 × 4 Mueller matrix. The closed cycle magneto-cryostat sub-system provides sample temperatures between room temperature and 1.4 K and magnetic fields up to 8 T, enabling the detection of transverse and longitudinal magnetic field-induced birefringence. We discuss theoretical background and practical realization of the integrated mid-infrared, far-infrared, and terahertz optical Hall effect instrument, as well as acquisition of optical Hall effect data and the corresponding model analysis procedures. Exemplarily, epitaxial graphene grown on 6H-SiC, a tellurium doped bulk GaAs sample and an AlGaN/GaN high electron mobility transistor structure are investigated. The selected experimental datasets display the full spectral, magnetic field and temperature range of the instrument and demonstrate data analysis strategies. Effects from free charge carriers in two dimensional confinement and in a volume material, as well as quantum mechanical effects (inter-Landau-level transitions) are observed and discussed exemplarily.

Kühne, P., E-mail: kuehne@huskers.unl.edu; Schubert, M., E-mail: schubert@engr.unl.edu; Hofmann, T., E-mail: thofmann@engr.unl.edu [Department of Electrical Engineering and Center for Nanohybrid Functional Materials, University of Nebraska-Lincoln, Lincoln, Nebraska 68588 (United States); Herzinger, C. M., E-mail: cherzinger@jawoollam.com; Woollam, J. A., E-mail: jwoollam@jawoollam.com [J. A. Woollam Co., Inc., 645 M Street, Suite 102, Lincoln, Nebraska 68508-2243 (United States)

2014-07-15T23:59:59.000Z

364

A tunable metamaterial dependent on electric field at terahertz with barium strontium titanate thin film  

SciTech Connect (OSTI)

A tunable metamaterial with resonance frequency at terahertz (THz) was developed. Electromagnetic response of the metamaterial was characterized with THz time domain spectrometer at various direct current electric fields. The resonance frequency increased monotonously with increasing electric field. The finite difference time domain method was used to simulate the transmission spectra of the metamaterial at THz frequencies. By comparing the simulated resonance frequency with the experimental curve, dielectric property of the Ba{sub 0.6}Sr{sub 0.4}TiO{sub 3} (BST60) thin film at THz, over 0–33?kV/cm, was evaluated.

Bian, Yanlong; Zhai, Jiwei, E-mail: apzhai@tongji.edu.cn [Function Materials Research Laboratory, Tongji University, Shanghai 200092 (China); Wu, Chao; Li, Hongqiang [Department of Physics Science and Engineering, Tongji University, Shanghai 200092 (China)

2014-01-27T23:59:59.000Z

365

Terahertz imaging of sub-wavelength particles with Zenneck surface waves  

SciTech Connect (OSTI)

Impact of sub-wavelength-size dielectric particles on Zenneck surface waves on planar metallic antennas is investigated at terahertz (THz) frequencies with THz near-field probe microscopy. Perturbations of the surface waves show the particle presence, despite its sub-wavelength size. The experimental configuration, which utilizes excitation of surface waves at metallic edges, is suitable for THz imaging of dielectric sub-wavelength size objects. As a proof of concept, the effects of a small strontium titanate rectangular particle and a titanium dioxide sphere on the surface field of a bow-tie antenna are experimentally detected and verified using full-wave simulations.

Navarro-Cía, M., E-mail: m.navarro@imperial.ac.uk [Optical and Semiconductor Devices Group, Department of Electrical and Electronic Engineering, Imperial College London, London SW7 2BT (United Kingdom); Centre for Plasmonics and Metamaterials, Imperial College London, London SW7 2AZ (United Kingdom); Centre for Terahertz Science and Engineering, Imperial College London, London SW7 2AZ (United Kingdom); Department of Electronic and Electrical Engineering, University College London, Torrington Place, London WC1E 7JE (United Kingdom); Natrella, M.; Graham, C.; Renaud, C. C.; Seeds, A. J.; Mitrofanov, O., E-mail: o.mitrofanov@ucl.ac.uk [Department of Electronic and Electrical Engineering, University College London, Torrington Place, London WC1E 7JE (United Kingdom); Dominec, F.; Kužel, P., E-mail: kuzelp@fzu.cz [Institute of Physics, Academy of Sciences of the Czech Republic, Na Slovance 2, 182 21 Prague 8 (Czech Republic); Delagnes, J. C.; Mounaix, P., E-mail: p.mounaix@loma.u-bordeaux1.fr [LOMA, Bordeaux 1 University, CNRS UMR 4798, 351 cours de la Libération, 33405 Talence (France)

2013-11-25T23:59:59.000Z

366

Feasibility of terahertz lasing in optically pumped epitaxial multiple graphene layer structures  

SciTech Connect (OSTI)

A multiple graphene layer (MGL) structure with a stack of GLs and a highly conducting bottom GL on SiC substrate pumped by optical radiation is considered as an active region of terahertz and far infrared lasers with external metal mirrors. The dynamic conductivity of the MGL structure is calculated as a function of the signal frequency, the number of GLs, and the optical pumping intensity. The utilization of optically pumped MGL structures might provide the achievement of lasing with the frequencies of about 1 THz at room temperature due to a high efficiency of pumping.

Ryzhii, V.; Ryzhii, M.; Satou, A. [Computational Nanoelectronics Laboratory, University of Aizu, Aizu-Wakamatsu 965-8580 (Japan); Japan Science and Technology Agency, CREST, Tokyo 107-0075 (Japan); Otsuji, T. [Japan Science and Technology Agency, CREST, Tokyo 107-0075 (Japan); Research Institute of Electrical Communication, Tohoku University, Sendai 980-8577 (Japan); Dubinov, A. A.; Aleshkin, V. Ya. [Institute for Physics of Microstructures, Russian Academy of Sciences, Nizhny Novgorod 603950 (Russian Federation)

2009-10-15T23:59:59.000Z

367

Intense terahertz emission from relativistic circularly polarized laser pulses interaction with overdense plasmas  

SciTech Connect (OSTI)

During the interaction of a relativistic circularly polarized laser pulse with an overdense plasma target, the longitudinal motion of bunches of electrons under the action of light pressure and electrostatic restore force can emit intense terahertz (THz) pulses. This mechanism allows high pump laser intensity and large electron number participating in the emission. Two-dimensional particle-in-cell simulations are carried out to investigate the THz emission. The results suggest that such a source can produce remarkably intense THz pulses with energy of several mJ/sr and power of tens of gigawatts, which could find applications in nonlinear studies and relativistic laser-plasma interaction diagnostics.

Chen, Zi-Yu; Li, Xiao-Ya [National Key Laboratory of Shock Wave and Detonation Physics, Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang 621900 (China)] [National Key Laboratory of Shock Wave and Detonation Physics, Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang 621900 (China); Yu, Wei [Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China)] [Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China)

2013-10-15T23:59:59.000Z

368

Liquid crystal terahertz phase shifters with functional indium-tin-oxide nanostructures for biasing and alignment  

SciTech Connect (OSTI)

Indium Tin Oxide (ITO) nanowhiskers (NWhs) obliquely evaporated by electron-beam glancing-angle deposition can serve simultaneously as transparent electrodes and alignment layer for liquid crystal (LC) devices in the terahertz (THz) frequency range. To demonstrate, we constructed a THz LC phase shifter with ITO NWhs. Phase shift exceeding ?/2 at 1.0 THz was achieved in a ?517??m-thick cell. The phase shifter exhibits high transmittance (?78%). The driving voltage required for quarter-wave operation is as low as 5.66?V (rms), compatible with complementary metal-oxide-semiconductor (CMOS) and thin-film transistor (TFT) technologies.

Yang, Chan-Shan [Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Tang, Tsung-Ta [Taiwan Semiconductor Manufacturing Company, Hsinchu, Taiwan (China); Pan, Ru-Pin [Department of Electrophysics, National Chiao Tung University, Hsinchu 30078, Taiwan (China); Yu, Peichen [Department of Photonics and Institute of Electro-Optical Engineering, National Chiao Tung University, Hsinchu 30010, Taiwan (China); Pan, Ci-Ling, E-mail: clpan@phys.nthu.edu.tw [Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Frontier Research Center on Fundamental and Applied Science of Matters, Hsinchu 30013, Taiwan (China)

2014-04-07T23:59:59.000Z

369

Voltage-tunable terahertz and infrared photodetectors based on double-graphene-layer structures  

SciTech Connect (OSTI)

We propose and theoretically substantiate the concept of terahertz and infrared photodetectors using the resonant radiative transitions between graphene layers (GLs) in double-GL structures. The calculated absorption spectrum and the spectral characteristics of the photodetector responsivity exhibit sharp resonant maxima at the photon energies in a wide range. The resonant maxima can be tuned by the applied voltage. We compare the photodetector responsivity with that of the GL p-i-n photodiodes and quantum-well infrared photodetectors. Weak temperature dependences of the photocurrent and dark current enable the effective operation of the proposed photodetector at room temperature.

Ryzhii, V., E-mail: v-ryzhii@riec.tohoku.ac.jp [Research Institute for Electrical Communication, Tohoku University, Sendai 980-8577 (Japan); Institute of Ultra High Frequency Semiconductor Electronics, Russian Academy of Sciences, Moscow 111005 (Russian Federation); Otsuji, T. [Research Institute for Electrical Communication, Tohoku University, Sendai 980-8577 (Japan); Aleshkin, V. Ya.; Dubinov, A. A. [Institute for Physics of Microstructures of Russian Academy of Sciences, and Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod 603950 (Russian Federation); Ryzhii, M. [Department of Computer Science and Engineering, University of Aizu, Aizu-Wakamatsu 965-8580 (Japan); Mitin, V. [Department of Electrical Engineering, University at Buffalo, Buffalo, New York 1460-1920 (United States); Shur, M. S. [Department of Electrical, Electronics, and System Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States)

2014-04-21T23:59:59.000Z

370

Propagation of terahertz electromagnetic wave in plasma with inhomogeneous collision frequency  

SciTech Connect (OSTI)

In this paper, we investigate the absorption spectra of terahertz electromagnetic wave in plasma with inhomogeneous collision frequency. Profiles are introduced to describe the non-uniformity of collision frequency. It is interesting to find that when the plasma is collision frequency inhomogeneous, the absorption spectrum would decreases faster than that in uniform plasma. And the rate of decreasing would be different when the profile changes. Two parameters are set up to predict how the profiles affect the absorption spectra. Furthermore, the effects of electron density are also considered.

Tian, Yuan; Han, YiPing; Ling, YingJie [School of Physics and Optoelectronic Engineering, Xidian University, Xi'an 710071 (China)] [School of Physics and Optoelectronic Engineering, Xidian University, Xi'an 710071 (China); Ai, Xia [National Laboratory of Science and Technology on Antennas and Microwaves Xidian University, Xi'an 710071 (China)] [National Laboratory of Science and Technology on Antennas and Microwaves Xidian University, Xi'an 710071 (China)

2014-02-15T23:59:59.000Z

371

Non-uniform absorption of terahertz radiation on superconducting hot electron bolometer microbridges  

SciTech Connect (OSTI)

We interpret the experimental observation of a frequency-dependence of superconducting hot electron bolometer (HEB) mixers by taking into account the non-uniform absorption of the terahertz radiation on the superconducting HEB microbridge. The radiation absorption is assumed to be proportional to the local surface resistance of the HEB microbridge, which is computed using the Mattis-Bardeen theory. With this assumption the dc and mixing characteristics of a superconducting niobium-nitride (NbN) HEB device have been modeled at frequencies below and above the equilibrium gap frequency of the NbN film.

Miao, W.; Zhang, W.; Zhong, J. Q.; Shi, S. C., E-mail: scshi@mail.pmo.ac.cn [Purple Mountain Observatory, CAS, 2 West Beijing Road, Nanjing 210008 (China); Delorme, Y.; Lefevre, R.; Feret, A.; Vacelet, T. [Observeratoire de Paris, 61 avenue de l'Observatoire, Paris 75014 (France)

2014-02-03T23:59:59.000Z

372

Enhancing the energy of terahertz radiation from plasma produced by intense femtosecond laser pulses  

SciTech Connect (OSTI)

Terahertz (THz) radiation from atomic clusters illuminated by intense femtosecond laser pulses is investigated. By studying the angular distribution, polarization properties and energy dependence of THz waves, we aim to obtain a proper understanding of the mechanism of THz generation. The properties of THz waves measured in this study differ from those predicted by previously proposed mechanisms. To interpret these properties qualitatively, we propose that the radiation is generated by time-varying quadrupoles, which are produced by the ponderomotive force of the laser pulse.

Jahangiri, Fazel [Advanced Research Center for Beam Science, ICR, Kyoto University, Kyoto (Japan) [Advanced Research Center for Beam Science, ICR, Kyoto University, Kyoto (Japan); Laser and Plasma Research Institute, Shahid Beheshti University, Tehran (Iran, Islamic Republic of); Hashida, Masaki; Tokita, Shigeki; Sakabe, Shuji [Advanced Research Center for Beam Science, ICR, Kyoto University, Kyoto (Japan) [Advanced Research Center for Beam Science, ICR, Kyoto University, Kyoto (Japan); Department of Physics, GSS, Kyoto University, Kyoto (Japan); Nagashima, Takeshi; Hangyo, Masanori [Department of Physics, GSS, Kyoto University, Kyoto (Japan) [Department of Physics, GSS, Kyoto University, Kyoto (Japan); Institute of Laser Engineering, Osaka University, Osaka (Japan)

2013-05-13T23:59:59.000Z

373

Lorentz Coherence and the Proton Form Factor  

E-Print Network [OSTI]

The dipole cutoff behavior for the proton form factor has been and still is one of the major issues in high-energy physics. It is shown that this dipole behavior comes from the coherence between the Lorentz contraction of the proton size and the decreasing wavelength of the incoming photon signal. The contraction rates are the same for both cases. This form of coherence is studied also in the momentum-energy space. The coherence effect in this space can be explained in terms of two overlapping wave functions.

Kim, Young S

2015-01-01T23:59:59.000Z

374

Spatial distribution of average charge state and deposition rate in high power impulse magnetron sputtering of copper  

SciTech Connect (OSTI)

The spatial distribution of copper ions and atoms in high power impulse magnetron sputtering (HIPIMS) discharges was determined by (i) measuring the ion current to electrostatic probes and (ii) measuring the film thickness by profilometry. A set of electrostatic and collection probes were placed at different angular positions and distances from the target surface. The angular distribution of the deposition rate and the average charge state of the copper species (including ions and neutrals) were deduced.The discharge showed a distinct transition to a high current mode dominated by copper self-sputtering when the applied voltage exceeded the threshold of 535 V. For a lower voltage, the deposition rate was very low and the average charge state was found to be less than 0.4. For higher voltage (and average power), the absolute deposition rates were much higher, but they were smaller than the corresponding direct current (DC) rates if normalized to the same average power. At the high voltage level, the spatial distribution of the average charge state showed some similarities with the distribution of the magnetic field, suggesting that the generation and motion of copper ions is affected by magnetized electrons. At higher voltage, the average charge state increases with the distance from the target and locally may exceed unity, indicating the presence of significant amounts of doubly charged copper ions.

Anders, Andre; Horwat, David; Anders, Andre

2008-05-10T23:59:59.000Z

375

High-power RF testing of a 352-MHZ fast-ferrite RF cavity tuner at the Advanced Photon Source.  

SciTech Connect (OSTI)

A 352-MHz fast-ferrite rf cavity tuner, manufactured by Advanced Ferrite Technology, was high-power tested on a single-cell copper rf cavity at the Advanced Photon Source. These tests measured the fast-ferrite tuner performance in terms of power handling capability, tuning bandwidth, tuning speed, stability, and rf losses. The test system comprises a single-cell copper rf cavity fitted with two identical coupling loops, one for input rf power and the other for coupling the fast-ferrite tuner to the cavity fields. The fast-ferrite tuner rf circuit consists of a cavity coupling loop, a 6-1/8-inch EIA coaxial line system with directional couplers, and an adjustable 360{sup o} mechanical phase shifter in series with the fast-ferrite tuner. A bipolar DC bias supply, controlled by a low-level rf cavity tuning loop consisting of an rf phase detector and a PID amplifier, is used to provide a variable bias current to the tuner ferrite material to maintain the test cavity at resonance. Losses in the fast-ferrite tuner are calculated from cooling water calorimetry. Test data will be presented.

Horan, D.; Cherbak, E.; Accelerator Systems Division (APS)

2006-01-01T23:59:59.000Z

376

Design and 3D simulation of a two-cavity wide-gap relativistic klystron amplifier with high power injection  

SciTech Connect (OSTI)

By using an electromagnetic particle-in-cell (PIC) code, an S-band two-cavity wide-gap klystron amplifier (WKA) loaded with washers/rods structure is designed and investigated for high power injection application. Influences of the washers/rods structure on the high frequency characteristics and the basic operation of the amplifier are presented. Generally, the rod structure has great impacts on the space-charge potential depression and the resonant frequency of the cavities. Nevertheless, if only the resonant frequency is tuned to the desired operation frequency, effects of the rod size on the basic operation of the amplifier are expected to be very weak. The 3-dimension (3-D) PIC simulation results show an output power of 0.98 GW corresponding to an efficiency of 33% for the WKA, with a 594 keV, 5 kA electron beam guided by an external magnetic field of 1.5 Tesla. Moreover, if a conductive plane is placed near the output gap, such as the electron collector, the beam potential energy can be further released, and the RF power can be increased to about 1.07 GW with the conversion efficiency of about 36%.

Bai Xianchen; Yang Jianhua; Zhang Jiande [College of Optoelectronic Science and Engineering, National University of Defense Technology, Changsha 410073 (China)

2012-08-15T23:59:59.000Z

377

Quantitative characterization of the water trimer torsional manifold by terahertz laser spectroscopy and theoretical analysis. II. ,,H2O...3  

E-Print Network [OSTI]

Quantitative characterization of the water trimer torsional manifold by terahertz laserLaughlin,c) Christy J. Keoshian, Ernest Michael, Jeff D. Cruzan,d) and Richard J. Saykallye) Department of Chemistry, University of California, Berkeley, California 94720 Ad van der Avoirdf) Institute of Theoretical Chemistry

Cohen, Ronald C.

378

Development of an electro-optic resonator probe for Terahertz imaging R. Mueckstein, Huiyun Liu, and O. Mitrofanov  

E-Print Network [OSTI]

Development of an electro-optic resonator probe for Terahertz imaging R. Mueckstein, Huiyun Liu, Abstract: We introduce the concept of an electro-optic resonator to improve resolution and enhance. The optimum design in terms of 3dB-bandwidth, reflectivity, and electro-optic enhancement is deduced

Haddadi, Hamed

379

Terahertz Time-Domain Spectroscopy Study of Silica Aerogels and Adsorbed Molecular Jiangquan Zhang and D. Grischkowsky*  

E-Print Network [OSTI]

Terahertz Time-Domain Spectroscopy Study of Silica Aerogels and Adsorbed Molecular Vapors Jiangquan time-domain spectroscopy (THz-TDS) study of hydrophobic and hydrophilic silica aerogels, and the adsorption of several molecular vapors in the hydrophilic silica aerogel. The hydrophobic and hydrophilic

380

Far-infrared optical and dielectric response of ZnS measured by terahertz time-domain spectroscopy  

E-Print Network [OSTI]

Far-infrared optical and dielectric response of ZnS measured by terahertz time-domain spectroscopy material in the infrared and far-infrared region.1 It plays a vital role in being used as infrared windows the frequency-dependent optical properties and complex di- electric response of ZnS over a broad far-infrared

Note: This page contains sample records for the topic "high-power coherent terahertz" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

High-power, hybrid Er:fiber/Tm:fiber frequency comb source in the 2 {\\mu}m wavelength region  

E-Print Network [OSTI]

We present a 2-\\mum frequency comb based on a reliable mode-locked Er:fiber laser with 100 MHz repetition rate. After shifting the spectrum of the amplified Er:fiber comb to longer wavelengths, a single-clad Tm/Ho:fiber is used as a self-pumped pre-amplifier to generate a coherent and broadband spectrum centered at 1.93 \\mum. Subsequently, a cladding-pumped Tm:fiber amplifier boosts the system to a maximum output power of 4.8 W at 1.96 \\mum. After compression in a compact grating compressor, our amplified Er:fiber/Tm:fiber hybrid system delivers as much as 2.9 W with a pulse duration of 141 fs. The system's comb properties are examined via heterodyne measurement.

Adler, Florian

2012-01-01T23:59:59.000Z

382

Managing coherence via put/get windows  

DOE Patents [OSTI]

A method and apparatus for managing coherence between two processors of a two processor node of a multi-processor computer system. Generally the present invention relates to a software algorithm that simplifies and significantly speeds the management of cache coherence in a message passing parallel computer, and to hardware apparatus that assists this cache coherence algorithm. The software algorithm uses the opening and closing of put/get windows to coordinate the activated required to achieve cache coherence. The hardware apparatus may be an extension to the hardware address decode, that creates, in the physical memory address space of the node, an area of virtual memory that (a) does not actually exist, and (b) is therefore able to respond instantly to read and write requests from the processing elements.

Blumrich, Matthias A. (Ridgefield, CT); Chen, Dong (Croton on Hudson, NY); Coteus, Paul W. (Yorktown Heights, NY); Gara, Alan G. (Mount Kisco, NY); Giampapa, Mark E. (Irvington, NY); Heidelberger, Philip (Cortlandt Manor, NY); Hoenicke, Dirk (Ossining, NY); Ohmacht, Martin (Yorktown Heights, NY)

2011-01-11T23:59:59.000Z

383

Coherence properties of the radiation from FLASH  

E-Print Network [OSTI]

FLASH is the first free electron laser user facility operating in the vacuum ultraviolet and soft x-ray wavelength range. Many user experiments require knowledge of the spatial and temporal coherence properties of the radiation. In this paper we present an analysis of the coherence properties of the radiation for the fundamental and for the higher odd frequency harmonics. We show that temporal and spatial coherence reach maximum close to the FEL saturation but may degrade significantly in the post-saturation regime. We also find that the pointing stability of short FEL pulses is limited due to the fact that non-azimuthal FEL eigenmodes are not sufficiently suppressed. We discuss possible ways for improving the degree of transverse coherence and the pointing stability.

Schneidmiller, E A

2015-01-01T23:59:59.000Z

384

Coherent neutrino scattering in dark matter detectors  

E-Print Network [OSTI]

Coherent elastic neutrino-nucleus and weakly interacting massive particle-nucleus interaction signatures are expected to be quite similar. This paper discusses how a next-generation ton-scale dark matter detector could ...

Anderson, Alexander John

385

Managing coherence via put/get windows  

DOE Patents [OSTI]

A method and apparatus for managing coherence between two processors of a two processor node of a multi-processor computer system. Generally the present invention relates to a software algorithm that simplifies and significantly speeds the management of cache coherence in a message passing parallel computer, and to hardware apparatus that assists this cache coherence algorithm. The software algorithm uses the opening and closing of put/get windows to coordinate the activated required to achieve cache coherence. The hardware apparatus may be an extension to the hardware address decode, that creates, in the physical memory address space of the node, an area of virtual memory that (a) does not actually exist, and (b) is therefore able to respond instantly to read and write requests from the processing elements.

Blumrich, Matthias A. (Ridgefield, CT); Chen, Dong (Croton on Hudson, NY); Coteus, Paul W. (Yorktown Heights, NY); Gara, Alan G. (Mount Kisco, NY); Giampapa, Mark E. (Irvington, NY); Heidelberger, Philip (Cortlandt Manor, NY); Hoenicke, Dirk (Ossining, NY); Ohmacht, Martin (Yorktown Heights, NY)

2012-02-21T23:59:59.000Z

386

Coherent regulation in yeast cell cycle network  

E-Print Network [OSTI]

We define a measure of coherent activity for gene regulatory networks, a property that reflects the unity of purpose between the regulatory agents with a common target. We propose that such harmonious regulatory action is desirable under a demand for energy efficiency and may be selected for under evolutionary pressures. We consider two recent models of the cell-cycle regulatory network of the budding yeast, Saccharomyces cerevisiae, as a case study and calculate their degree of coherence. A comparison with random networks of similar size and composition reveals that the yeast's cell-cycle regulation is wired to yield and exceptionally high level of coherent regulatory activity. We also investigate the mean degree of coherence as a function of the network size, connectivity and the fraction of repressory/activatory interactions.

Nese Aral; Alkan Kabakcioglu

2014-12-14T23:59:59.000Z

387

Extended Coherence Time with Atom-Number Squeezed Sources  

E-Print Network [OSTI]

Coherence properties of Bose-Einstein condensates offer the potential for improved interferometric phase contrast. However, decoherence effects due to the mean-field interaction shorten the coherence time, thus limiting potential sensitivity. In this work, we demonstrate increased coherence times with number squeezed states in an optical lattice using the decay of Bloch oscillations to probe the coherence time. We extend coherence times by a factor of 2 over those expected with coherent state BEC interferometry. We observe quantitative agreement with theory both for the degree of initial number squeezing as well as for prolonged coherence times.

Wei Li; Ari K. Tuchman; Hui-Chun Chien; Mark A. Kasevich

2006-09-02T23:59:59.000Z

388

Source of coherent short wavelength radiation  

DOE Patents [OSTI]

An apparatus for producing coherent radiation ranging from X-rays to the far ultraviolet (i.e., 1 Kev to 10 eV) utilizing the Compton scattering effect. A photon beam from a laser is scattered on a high energy electron bunch from a pulse power linac. The short wavelength radiation produced by such scattering has sufficient intensity and spatial coherence for use in high resolution applications such as microscopy.

Villa, Francesco (Alameda, CA)

1990-01-01T23:59:59.000Z

389

Quantum Coherence in a Superfluid Josephson Junction  

SciTech Connect (OSTI)

We report a new kind of experiment in which we take an array of nanoscale apertures that form a superfluid {sup 4}He Josephson junction and apply quantum phase gradients directly along the array. We observe collective coherent behaviors from aperture elements, leading to quantum interference. Connections to superconducting and Bose-Einstein condensate Josephson junctions as well as phase coherence among the superfluid aperture array are discussed.

Narayana, Supradeep; Sato, Yuki [Rowland Institute at Harvard, Harvard University, Cambridge, Massachusetts 02142 (United States)

2011-02-04T23:59:59.000Z

390

EECS 598 Special Topics 005: Laser Plasma Diagnostics High power laser pulses are used to both create and diagnose high-energy  

E-Print Network [OSTI]

EECS 598 Special Topics 005: Laser Plasma Diagnostics High power laser pulses are used to both to relativistic-intensity femtosecond pulses. We will explore the diagnostics used to characterize high-energy density plasmas through optical and other radiation measurements as well as backlighting techniques. Other

Sarabandi, Kamal

391

Free-Standing LiNi0.5Mn1.5O4/Carbon Nanofiber Network Film as Light-Weight and High-Power  

E-Print Network [OSTI]

Free-Standing LiNi0.5Mn1.5O4/Carbon Nanofiber Network Film as Light-Weight and High-Power Cathode Pure carbon nanofiber (CNF) network without LiNi0.5Mn1.5O4 was tested in the voltage window of 3.5-5 V

Zhou, Chongwu

392

Conference 5739, SPIE International Symposium Integrated Optoelectronic Devices, 22-27 Jan 2005, San Jose, CA Development of high power green light emitting diode dies in  

E-Print Network [OSTI]

, San Jose, CA Development of high power green light emitting diode dies in piezoelectric Ga in green light emitting diodes is one of the big challenges towards all-solid- state lighting. The prime,3], and commercialization [4,5] of high brightness light emitting diodes LEDs has led to a 1.82 Billion-$/year world market

Wetzel, Christian M.

393

HIGH POWER COUPLER FOR THE TESLA SUPERSTRUCTURE , J. T. Susta, G. Cheng, AMAC International Inc., Newport News, VA 23606, U.S.A.  

E-Print Network [OSTI]

HIGH POWER COUPLER FOR THE TESLA SUPERSTRUCTURE CAVITIES* Q. S. Shu# , J. T. Susta, G. Cheng, AMAC are required to reduce this risk. The TESLA superstructure cavity requires a new coupler for the higher power TESLA cylindrical ceramic windows, uses two planar disc windows separated by a vacuum space

Boyer, Edmond

394

Micro capillary pumped loop system for a cooling high power device Chin-Tsan Wang a,*, Tzong-Shyng Leu b  

E-Print Network [OSTI]

Micro capillary pumped loop system for a cooling high power device Chin-Tsan Wang a,*, Tzong-driven two-phase loop, configured on a micro capillary pumped loop (MCPL) system without an external power. The combination of micro-scale heat transfer and fluid dynamics along with high surface-to-volume ratios makes

Leu, Tzong-Shyng "Jeremy"

395

Global coherence of dust density waves  

SciTech Connect (OSTI)

The coherence of self-excited three-dimensional dust density waves has been experimentally investigated by comparing global and local wave properties. For that purpose, three-dimensional dust clouds have been confined in a radio frequency plasma with thermophoretic levitation. Global wave properties have been measured from the line-of-sight integrated dust density obtained from homogenous light extinction measurements. Local wave properties have been obtained from thin, two-dimensional illuminated laser slices of the cloud. By correlating the simultaneous global and local wave properties, the spatial coherence of the waves has been determined. We find that linear waves with small amplitudes tend to be fragmented, featuring an incoherent wave field. Strongly non-linear waves with large amplitudes, however, feature a strong spatial coherence throughout the dust cloud, indicating a high level of synchronization.

Killer, Carsten; Melzer, André [Institut für Physik, Ernst-Moritz-Arndt-Universität Greifswald, 17489 Greifswald (Germany)

2014-06-15T23:59:59.000Z

396

Store-operate-coherence-on-value  

DOE Patents [OSTI]

A system, method and computer program product for performing various store-operate instructions in a parallel computing environment that includes a plurality of processors and at least one cache memory device. A queue in the system receives, from a processor, a store-operate instruction that specifies under which condition a cache coherence operation is to be invoked. A hardware unit in the system runs the received store-operate instruction. The hardware unit evaluates whether a result of the running the received store-operate instruction satisfies the condition. The hardware unit invokes a cache coherence operation on a cache memory address associated with the received store-operate instruction if the result satisfies the condition. Otherwise, the hardware unit does not invoke the cache coherence operation on the cache memory device.

Chen, Dong; Heidelberger, Philip; Kumar, Sameer; Ohmacht, Martin; Steinmacher-Burow, Burkhard

2014-11-18T23:59:59.000Z

397

Low-Cost Superconducting Wire for Wind Generators: High Performance, Low Cost Superconducting Wires and Coils for High Power Wind Generators  

SciTech Connect (OSTI)

REACT Project: The University of Houston will develop a low-cost, high-current superconducting wire that could be used in high-power wind generators. Superconducting wire currently transports 600 times more electric current than a similarly sized copper wire, but is significantly more expensive. The University of Houston’s innovation is based on engineering nanoscale defects in the superconducting film. This could quadruple the current relative to today’s superconducting wires, supporting the same amount of current using 25% of the material. This would make wind generators lighter, more powerful and more efficient. The design could result in a several-fold reduction in wire costs and enable their commercial viability of high-power wind generators for use in offshore applications.

None

2012-01-01T23:59:59.000Z

398

Post-processing of polymer foam tissue scaffolds with high power ultrasound: a route to increased pore interconnectivity, pore size and fluid transport  

E-Print Network [OSTI]

We expose thick polymer foam tissue scaffolds to high power ultrasound and study its effect on the openness of the pore architecture and fluid transport through the scaffold. Our analysis is supported by measurements of fluid uptake during insonification and imaging of the scaffold microstructure via x-ray computed tomography, scanning electron microscopy and acoustic microscopy. The ultrasonic treatment is found to increase the mean pore size by over 10%. More striking is the improvement in fluid uptake: for scaffolds with only 40% water uptake via standard immersion techniques, we can routinely achieve full saturation of the scaffold over approximately one hour of exposure. These desirable modifications occur with no loss of scaffold integrity and negligible mass loss, and are optimized when the ultrasound treatment is coupled to a pre-wetting stage with ethanol. Our findings suggest that high power ultrasound is a highly targetted and efficient means to promote pore interconnectivity and fluid transport in thick foam tissue scaffolds.

N J Watson; R K Johal; Y Reinwald; L J White; A M Ghaemmaghami; S P Morgan; F R A J Rose; M J W Povey; N G Parker

2013-02-18T23:59:59.000Z

399

Low-temperature thermodynamics with quantum coherence  

E-Print Network [OSTI]

We find a new characterization of low-temperature processes, which we call "cooling processes", incorporating quantum coherence in the model of thermodynamics for the first time. We derive necessary and sufficient conditions for the feasibility of state transitions under cooling processes. We also rigorously confirm the intuitive robustness of coherence against low-temperature thermal noise. Additionally, we develop the low-temperature "Gibbs-preserving" model, and by comparing our results on the two models, we argue that the latter is a poor approximation to physical processes.

Varun Narasimhachar; Gilad Gour

2014-10-02T23:59:59.000Z

400

Dental optical coherence domain reflectometry explorer  

DOE Patents [OSTI]

A hand-held, fiber optic based dental device with optical coherence domain reflectometry (OCDR) sensing capabilities provides a profile of optical scattering as a function of depth in the tissue at the point where the tip of the dental explorer touches the tissue. This system provides information on the internal structure of the dental tissue, which is then used to detect caries and periodontal disease. A series of profiles of optical scattering or tissue microstructure are generated by moving the explorer across the tooth or other tissue. The profiles are combined to form a cross-sectional, or optical coherence tomography (OCT), image.

Everett, Matthew J. (Livermore, CA); Colston, Jr., Billy W. (Livermore, CA); Sathyam, Ujwal S. (Livermore, CA); Da Silva, Luiz B. (Pleasanton, CA)

2001-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "high-power coherent terahertz" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

Development of a 10 kW High Temperature High Power Density Three-Phase AC-DC-AC SiC Converter  

SciTech Connect (OSTI)

This paper presents the development and experimental performance of a 10 kW, all SiC, 250 C junction temperature high-power-density three-phase ac-dc-ac converter. The electromagnetic interference filter, thermal system, high temperature package, and gate drive design are discussed in detail. Finally, tests confirming the feasibility and validating the theoretical basis of the prototype converter system are described.

Ning, Puqi [ORNL

2012-01-01T23:59:59.000Z

402

Wir schaffen Wissen heute fr morgen Daniela Kiselev, 4th High Power Targetry Workshop, 2.5.-6.5.2011, Malm, Sweden  

E-Print Network [OSTI]

.5.-6.5.2011, Malmö, Sweden 6.5.2011PSI, Paul Scherrer Institut Examination of a copper collimator irradiated.5.-6.5.2011, Malmö, Sweden 6.5.2011PSI, Contents ·Location, purpose and history of collimator KHE2 ·DPA calculation) ·Conclusion and outlook #12;Daniela Kiselev, 4th High Power Targetry Workshop, 2.5.-6.5.2011, Malmö, Sweden 6

McDonald, Kirk

403

Efficient terahertz-wave generation and its ultrafast optical modulation in charge ordered organic ferroelectrics  

SciTech Connect (OSTI)

Efficient terahertz (THz) wave generation in strongly correlated organic compounds ?-(ET){sub 2}I{sub 3} and ??-(ET){sub 2}IBr{sub 2} (ET:bis(ethylenedithio)-tetrathiafulvalene) was demonstrated. The spontaneous polarization induced by charge ordering or electronic ferroelectricity was revealed to trigger the THz-wave generation via optical rectification; the estimated 2nd-order nonlinear optical susceptibility for ?-(ET){sub 2}I{sub 3} is over 70 times larger than that for prototypical THz-source ZnTe. Ultrafast (<1 ps) and sensitive (?40%) photoresponse of the THz wave was observed for ?-(ET){sub 2}I{sub 3}, which is attributable to photoinduced quenching of the polarization accompanied by insulator(ferroelectric)-to-metal transition. Modulation of the THz wave was observed for ??-(ET){sub 2}IBr{sub 2} upon the poling procedure, indicating the alignment of polar domains.

Itoh, Hirotake, E-mail: hiroitoh@m.tohoku.ac.jp; Iwai, Shinichiro, E-mail: s-iwai@m.tohoku.ac.jp [Department of Physics, Tohoku University, Sendai 980-8578 (Japan); JST, CREST, Sendai 980-8578 (Japan); Itoh, Keisuke; Goto, Kazuki [Department of Physics, Tohoku University, Sendai 980-8578 (Japan); Yamamoto, Kaoru [Department of Applied Physics, Okayama University of Science, Okayama 700-0005 (Japan); Yakushi, Kyuya [Toyota Physical and Chemical Research Institute, Nagakute 480-1192 (Japan)

2014-04-28T23:59:59.000Z

404

Terahertz photomixing using plasma resonances in double-graphene layer structures  

SciTech Connect (OSTI)

We propose the concept of terahertz (THz) photomixing enabled by the interband electron transitions due to the absorption of modulated optical radiation in double-graphene layer (double-GL) structures and the resonant excitation of plasma oscillations. Using the developed double-GL photomixer (DG-PM) model, we describe its operation and calculate the device characteristics. The output power of the THz radiation exhibits sharp resonant peaks at the plasmonic resonant frequencies. The peak powers markedly exceed the output powers at relatively low frequencies. Due to relatively high quantum efficiency of optical absorption in GLs and short inter-GL transit time, the proposed DG-PM operating in the resonant plasma oscillation regime can surpass the photomixers based on the standard heterostructures.

Ryzhii, V.; Satou, A.; Otsuji, T. [Research Institute for Electrical Communication, Tohoku University, Sendai 980-8577 (Japan); Ryzhii, M. [Computational Nanoelectronics Laboratory, University of Aizu, Aizu-Wakamatsu 965-8580 (Japan); Mitin, V. [Department of Electrical Engineering, University at Buffalo, Buffalo, New York 1460-1920 (United States); Shur, M. S. [Department of Electrical, Electronics, and Systems Engineering and Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States)

2013-05-07T23:59:59.000Z

405

Intense terahertz emission from molecular beam epitaxy-grown GaAs/GaSb(001)  

SciTech Connect (OSTI)

Intense terahertz (THz) electromagnetic wave emission was observed in undoped GaAs thin films deposited on (100) n-GaSb substrates via molecular beam epitaxy. GaAs/n-GaSb heterostructures were found to be viable THz sources having signal amplitude 75% that of bulk p-InAs. The GaAs films were grown by interruption method during the growth initiation and using various metamorphic buffer layers. Reciprocal space maps revealed that the GaAs epilayers are tensile relaxed. Defects at the i-GaAs/n-GaSb interface were confirmed by scanning electron microscope images. Band calculations were performed to infer the depletion region and electric field at the i-GaAs/n-GaSb and the air-GaAs interfaces. However, the resulting band calculations were found to be insufficient to explain the THz emission. The enhanced THz emission is currently attributed to a piezoelectric field induced by incoherent strain and defects.

Sadia, Cyril P.; Laganapan, Aleena Maria; Agatha Tumanguil, Mae; Estacio, Elmer; Somintac, Armando; Salvador, Arnel [National Institute of Physics, University of the Philippines Diliman, Quezon City 1101 (Philippines); Que, Christopher T. [Physics Department, De La Salle University, 2401 Taft Avenue, Manila 1004 (Philippines); Yamamoto, Kohji; Tani, Masahiko [Research Center for Development of Far-Infrared Region, University of Fukui, Fukui 910-8507 (Japan)

2012-12-15T23:59:59.000Z

406

A high carrier injection terahertz quantum cascade laser based on indirectly pumped scheme  

SciTech Connect (OSTI)

A Terahertz quantum cascade laser with a rather high injection coupling strength based on an indirectly pumped scheme is designed and experimentally implemented. To effectively suppress leakage current, the chosen quantum cascade module of the device is based on a five-well GaAs/Al{sub 0.25}Ga{sub 0.75}As structure. The device lases up to 151?K with a lasing frequency of 2.67 THz. This study shows that the effect of higher energy states in carrier transport and the long-range tunnel coupling between states that belong to non-neighbouring modules have to be considered in quantum design of structures with a narrow injector barrier. Moreover, the effect of interface roughness scattering between the lasing states on threshold current is crucial.

Razavipour, S. G., E-mail: sgrazavi@uwaterloo.ca; Xu, C.; Wasilewski, Z. R.; Ban, D. [Department of Electrical and Computer Engineering, Waterloo Institute for Nanotechnology, University of Waterloo, 200 University Ave. W., Waterloo, Ontario N2L3G1 (Canada); Dupont, E.; Laframboise, S. R. [National Research Council, Blg. M-50, 1200 Montreal Rd., Ottawa, Ontario K1A0R6 (Canada); Chan, C. W. I.; Hu, Q. [Department of Electrical Engineering and Computer Science, Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

2014-01-27T23:59:59.000Z

407

On the role of terahertz field acceleration and beaming of surface plasmon generated ultrashort electron pulses  

SciTech Connect (OSTI)

A mechanism for control of the energy and pitch angle of surface plasmon accelerated electron pulses is proposed. Electrons generated via multi-photon absorption in a silver film on a glass prism are ponderomotively accelerated in the surface plasmon field excited by a 30 fs, 800?nm optical pulse. Through introduction of a single-cycle terahertz (THz) pulse, the energy spectrum and trajectory of the generated electron pulse can be controlled via the THz field strength. Generated electron pulses achieve peak kinetic energies up to 1.56?keV, while utilizing an incident optical field strength five times less than comparable plasmon accelerated electron pulses. These results demonstrate that THz pulses can be utilized to achieve tunable, high energy, trajectory controlled electron pulses necessary for various applications that require ultrafast electron pulse manipulation.

Greig, S. R., E-mail: sgreig@ualberta.ca; Elezzabi, A. Y., E-mail: elezzabi@ece.ualberta.ca [Ultrafast Optics and Nanophotonics Laboratory, Department of Electrical and Computer Engineering, University of Alberta, Edmonton T6G 2V4 (Canada)

2014-07-28T23:59:59.000Z

408

Electrically tunable terahertz wave modulator based on complementary metamaterial and graphene  

SciTech Connect (OSTI)

In this paper, we design and numerically demonstrate an electrically controllable light-matter interaction in a hybrid material/metamaterial system consisting of an artificially constructed cross cut-wire complementary metamaterial and an atomically thin graphene layer to realize terahertz (THz) wave modulator. By applying a bias voltage between the metamaterial and the graphene layer, this modulator can dynamically control the amplitude and phase of the transmitted wave near 1.43 THz. Moreover, the distributions of current density show that this large modulation depth can be attributed to the resonant electric field parallel to the graphene sheet. Therefore, the modulator performance indicates the enormous potential of graphene for developing sophisticated THz communication systems.

He, Xun-jun, E-mail: hexunjun@hrbust.edu.cn; Li, Teng-yue; Wang, Lei; Wang, Jian-min; Jiang, Jiu-xing [Department of Electronic Science and technology, School of Applied Sciences, Harbin University of Science and Technology, Harbin 150080 (China); Yang, Guo-hui; Meng, Fan-yi; Wu, Qun [Department of Electronic and Communications Engineering, School of Electronic Information Engineering, Harbin Institute of Technology, Harbin 150001 (China)

2014-05-07T23:59:59.000Z

409

Journal of the Korean Physical Society, Vol. 49, December 2006, pp. S309S313 High-Power Pulse Transformer for a 1.5-MW Magnetron of KSTAR LHCD  

E-Print Network [OSTI]

Transformer for a 1.5-MW Magnetron of KSTAR LHCD Microwave Application Sung-Duck Jang, Yoon-Gyu Son and Jong-power magnetron. The high power pulse transformer has the function of transferring pulse energy from a pulsed power source to a high-power load. A pulse transformer producing a pulse with a peak voltage of 45 k

410

Detection of terahertz radiation by tightly concatenated InGaAs field-effect transistors integrated on a single chip  

SciTech Connect (OSTI)

A tightly concatenated chain of InGaAs field-effect transistors with an asymmetric T-gate in each transistor demonstrates strong terahertz photovoltaic response without using supplementary antenna elements. We obtain the responsivity above 1000?V/W and up to 2000?V/W for unbiased and drain-biased transistors in the chain, respectively, with the noise equivalent power below 10{sup ?11} W/Hz{sup 0.5} in the unbiased mode of the detector operation.

Popov, V. V., E-mail: popov-slava@yahoo.co.uk [Kotelnikov Institute of Radio Engineering and Electronics (Saratov Branch), Russian Academy of Sciences, Saratov 410019 (Russian Federation); Yermolaev, D. M.; Shapoval, S. Yu. [Institute of Microelectronic Technology and High-Purity Materials, Russian Academy of Sciences, Chernogolovka, Moscow Region 142432 (Russian Federation); Maremyanin, K. V.; Gavrilenko, V. I. [Institute for Physics of Microstructures, Russian Academy of Sciences, Nizhny Novgorod 603950 (Russian Federation); Lobachevsky State University of Nizhni Novgorod, Nizhni Novgorod 603950 (Russian Federation); Zemlyakov, V. E.; Bespalov, V. A.; Yegorkin, V. I. [National Research University of Electronic Technology, Zelenograd, Moscow 124498 (Russian Federation); Maleev, N. A.; Ustinov, V. M. [Ioffe Physical Technical Institute, Russian Academy of Sciences, St. Petersburg 194021 (Russian Federation)

2014-04-21T23:59:59.000Z

411

DEVELOPMENT OF A 4 K STIRLING-TYPE PULSE TUBE CRYOCOOLER FOR A MOBILE TERAHERTZ DETECTION SYSTEM  

SciTech Connect (OSTI)

We discuss in this paper the design and development of a 4 K Stirling-type pulse tube cryocooler for a mobile terahertz detection system. This system integrates new heterodyne detector technology at terahertz frequencies with advancements of Stirling-type pulse tube technology that brings the advent of cooled detector sensitivities in a mobile, compact, and long duration operation system without degradation of sensitivity. To achieve this goal we reduced overall system size, input power, and temperature fluctuations and mechanical vibrations in order to maintain the detector sensitivity. The Stirling-type pulse tube cryocooler developed for this system is a hybrid design employing a He-4 pulse-tube cryocooler operating at 60 Hz and 2.5 MPa average pressure that precools a He-3 pulse tube cryocooler operating at 30 Hz and 1.0 MPa average pressure to achieve 4 K cooling for the terahertz receiver. The He-4 cryocooler employs stainless steel mesh regenerators for the first stage and ErPr spheres for the second stage, while the He-3 cryocooler employs stainless mesh for the first stage and ErPr spheres for the second stage with a layered rare-earth third stage regenerator. Design details and cooler performance goals are discussed.

Bradley, P. E.; Gerecht, E.; Radebaugh, R. [National Institute of Standards and Technology, Boulder, Colorado, 80305 (United States); Garaway, I. [National Institute of Standards and Technology, Boulder, Colorado, 80305 (United States); Technion-Israel Institute of Technology, Haifa (Israel)

2010-04-09T23:59:59.000Z

412

PHASE COHERENCE PHENOMENA IN DISORDERED SUPERCONDUCTORS  

E-Print Network [OSTI]

PHASE COHERENCE PHENOMENA IN DISORDERED SUPERCONDUCTORS A. LAMACRAFT AND B. D. SIMONS Cavendish on the quasi­particle properties of disordered superconductors. Again, attempts to develop a consistent theory has been formulated. Yet, a complete description of the phenomenology of the disordered superconductor

Simons, Ben

413

Coherent states in the fermionic Fock space  

E-Print Network [OSTI]

We construct the coherent states in the sense of Gilmore and Perelomov for the fermionic Fock space. Our treatment is from the outset adapted to the infinite-dimensional case. The fermionic Fock space becomes in this way a reproducing kernel Hilbert space of continuous holomorphic functions.

Robert Oeckl

2015-01-09T23:59:59.000Z

414

Coherent Radiation Effects in the LCLS Undulator  

SciTech Connect (OSTI)

For X-ray Free-Electron Lasers such as LCLS and TESLA FEL, a change in the electron energy while amplifying the FEL radiation can shift the resonance condition out of the bandwidth of the FEL. The largest sources of energy loss is the emission of incoherent undulator radiation. Because the loss per electron depends only on the undulator parameters and the beam energy, which are fixed for a given resonant wavelength, the average energy loss can be compensated for by a fixed taper of the undulator. Coherent radiation has a strong enhancement proportional to the number of electrons in the bunch for frequencies comparable to or longer than the bunch dimension. If the emitted coherent energy becomes comparable to that of the incoherent emission, it has to be included in the taper as well. However, the coherent loss depends on the bunch charge and the applied compression scheme and a change of these parameters would require a change of the taper. This imposes a limitation on the practical operation of Free-Electron Lasers, where the taper can only be adjusted manually. In this presentation we analyze the coherent emission of undulator radiation and transition undulator radiation for LCLS, and estimate whether the resulting energy losses are significant for the operation of LCLS.

Reiche, S.; /UCLA; Huang, Z.; /SLAC

2010-12-14T23:59:59.000Z

415

Interaction between the molecular coherent states for a discrete variable harmonic oscillator and the coherent radiation  

SciTech Connect (OSTI)

We used the dicrete variable three-dimmensional Charlier oscillator. For a system of molecules interacting with the coherent radiation field the temporal variation of the refractive index has been established.

Draganescu, Gheorghe Eugen [Department of Mechanics, Polytechnic University of Timisoara, Bd M Viteazu No1, Timisoara and Department of Physics, West University of Timisoara (Romania)

2012-08-17T23:59:59.000Z

416

Search for temporal coherence in the sky Erez N. Ribak  

E-Print Network [OSTI]

, related to longitudinal coherence by the speed of light c: c = lc / c. Generally, naturally occurring for naturally occurring coherence is in gravitational lensing by a small object, where the paths to the observer in astrophysical processes. Among others, synchrotron radiation, known to be polarized, can be also coherent over

Ribak, Erez

417

Coherent Time-Delayed Atom-Light Interferometer  

E-Print Network [OSTI]

We present experimental observations of interference between an atomic spin coherence and an optical field in a $\\Lambda$-type gradient echo memory. The interference is mediated by a strong classical field that couples a weak probe field to the atomic spin coherence through a resonant Raman transition. Interference can be observed between a prepared spin coherence and another propagating optical field, or between multiple $\\Lambda$ transitions driving a single spin coherence. In principle, the interference in each scheme can yield a near unity visibility and could be used as a coherent all-optical switch.

Campbell, G; Sparkes, B M; Lam, P K; Buchler, B C

2011-01-01T23:59:59.000Z

418

COHERENT LASER VISION SYSTEM (CLVS) OPTION PHASE  

SciTech Connect (OSTI)

The purpose of this research project was to develop a prototype fiber-optic based Coherent Laser Vision System (CLVS) suitable for DOE's EM Robotic program. The system provides three-dimensional (3D) vision for monitoring situations in which it is necessary to update the dimensional spatial data on the order of once per second. The system has total immunity to ambient lighting conditions.

Robert Clark

1999-11-18T23:59:59.000Z

419

Emergence of non-zonal coherent structures  

E-Print Network [OSTI]

Planetary turbulence is observed to self-organize into large-scale structures such as zonal jets and coherent vortices. One of the simplest models that retains the relevant dynamics of turbulent self-organization is a barotropic flow in a beta-plane channel with turbulence sustained by random stirring. Non-linear integrations of this model show that as the energy input rate of the forcing is increased, the homogeneity of the flow is first broken by the emergence of non-zonal, coherent, westward propagating structures and at larger energy input rates by the emergence of zonal jets. The emergence of both non-zonal coherent structures and zonal jets is studied using a statistical theory, Stochastic Structural Stability Theory (S3T). S3T directly models a second-order approximation to the statistical mean turbulent state and allows the identification of statistical turbulent equilibria and study of their stability. Using S3T, the bifurcation properties of the homogeneous state in barotropic beta-plane turbulence ...

Bakas, Nikolaos A

2015-01-01T23:59:59.000Z

420

Equatorial spread {ital F} effects on an HF path: Doppler spread, spatial coherence, and frequency coherence  

SciTech Connect (OSTI)

In August 1990 we participated in the Equatorial Ionospheric Studies sounding rocket campaign near Kwajalein Atoll in the equatorial Pacific region. The campaign included measurements of plasma density using rocket probes and coherent and incoherent scatter radar. During the campaign we fielded high-frequency ionospheric sounders over a bistatic path between Maloelap Atoll and Bikini Atoll in the Marshall Islands. The distance between the transmitters and receivers was 700 km; the ionospheric-reflection region was at 10.18; {degree}N, 168.40;{degree}E, near the magnetic equator. We made three types of measurements: Doppler spread and spatial coherence for a single-frequency CW path; frequency coherence of multiple CW paths; and Doppler spread and time-delay spread for a 60-kHz bandwidth path. We obtained such data over a period of 2 weeks for approximately 2 hours each evening; during this period spread {ital F} was common. Fifty percent of the evenings showed Doppler spread of greater than 6 Hz at the {minus}10 dB level (relative to the peak signal power) and greater than 15 Hz at the {minus}30 dB level. Forty percent of the evenings showed spatial coherence distance of less than 180 m in the direction normal to the bistatic path; 40{percent} of the evenings showed spatial coherence of less than 75 m in the direction parallel to the path. Seventy-five percent of the evenings showed coherence bandwidths of less than 1.5 kHz. {copyright} 1999 American Geophysical Union

Fitzgerald, T.J.; Argo, P.E.; Carlos, R.C. [Los Alamos National Laboratory, Los Alamos, New Mexico (United States)] [Los Alamos National Laboratory, Los Alamos, New Mexico (United States)

1999-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "high-power coherent terahertz" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

Theory and measurement of plasmonic terahertz detector response to large signals  

SciTech Connect (OSTI)

Electron gas in the conduction channel of a Field Effect Transistor (FET) can support collective plasma oscillations tunable by the gate voltage. In the Dyakonov-Shur terahertz (THz) detector, nonlinearities in the plasma wave propagation in the gated channel of a FET lead to a constant source-to-drain voltage providing the detector output. We present the detector theory in the frame of the hydrodynamic model using the electron plasma Navier-Stokes and thermal transport equations, thus fully accounting for the hydrodynamic non-linearity, the viscosity, and pressure gradients in the detector response. Both resonant and broadband operations of the high electron mobility transistor (HEMT) based plasmonic detectors are described by this model. The relation between the electron channel density and gate voltage was modeled by the unified charge control model applicable both above and below the threshold voltage. The theoretical results are compared with the response measured in the short channel InGaAs HEMT and the analytical approximation. The THz source was operating at 1.63 THz, and the response was measured at varying signal intensities. The response of the detector operated in the open drain mode was measured above and below the threshold, and the theoretical and experimental results are shown to be in good agreement.

Rudin, S.; Rupper, G. [Army Research Laboratory, 2800 Powder Mill Road, Adelphi, Maryland 20783 (United States); Gutin, A.; Shur, M. [Rensselaer Polytechnic Institute, Troy, New York 12180 (United States)

2014-02-14T23:59:59.000Z

422

Tunability of the terahertz space-charge modulation in a vacuum microdiode  

SciTech Connect (OSTI)

Under certain conditions, space-charge limited emission in vacuum microdiodes manifests as clearly defined bunches of charge with a regular size and interval. The frequency corresponding to this interval is in the terahertz range. In this computational study, it is demonstrated that, for a range of parameters, conducive to generating THz frequency oscillations, the frequency is dependant only on the cold cathode electric field and on the emitter area. For a planar micro-diode of given dimension, the modulation frequency can be easily tuned simply by varying the applied potential. Simulations of the microdiode are done for 84 different combinations of emitter area, applied voltage, and gap spacing, using a molecular dynamics based code with exact Coulomb interaction between all electrons in the vacuum gap, which is of the order 100. It is found, for a fixed emitter area, that the frequency of the pulse train is solely dependant on the vacuum electric field in the diode, described by a simple power law. It is also found that, for a fixed value of the electric field, the frequency increases with diminishing size of the emitting spot on the cathode. Some observations are made on the spectral quality, and how it is affected by the gap spacing in the diode and the initial velocity of the electrons.

Jonsson, P.; Ilkov, Marjan; Manolescu, A.; Valfells, A. [School of Science and Engineering, Reykjavik University, 101 Reykjavik (Iceland); Pedersen, A. [Science Institute, University of Iceland, 101 Reykjavik (Iceland)

2013-02-15T23:59:59.000Z

423

Harmonic mode competition in a terahertz gyrotron backward-wave oscillator  

SciTech Connect (OSTI)

Electron cyclotron maser interactions at terahertz (THz) frequencies require a high-order-mode structure to reduce the wall loss to a tolerable level. To generate THz radiation, it is also essential to employ cyclotron harmonic resonances to reduce the required magnetic field strength to a value within the capability of the superconducting magnets. However, much weaker harmonic interactions in a high-order-mode structure lead to serious mode competition problems. The current paper addresses harmonic mode competition in the gyrotron backward wave oscillator (gyro-BWO). We begin with a comparative study of the mode formation and oscillation thresholds in the gyro-BWO and gyromonotron. Differences in linear features result in far fewer 'windows' for harmonic operation of the gyro-BWO. Nonlinear consequences of these differences are examined in particle simulations of the multimode competition processes in the gyro-BWO, which shed light on the competition criteria between modes of different as well as the same cyclotron harmonic numbers. The viability of a harmonic gyro-BWO is assessed on the basis of the results obtained.

Kao, S. H.; Chiu, C. C.; Chang, P. C.; Wu, K. L.; Chu, K. R. [Department of Physics, National Taiwan University, Taipei 106, Taiwan (China)

2012-10-15T23:59:59.000Z

424

Quasi-optic synthetic phased-array terahertz John O'Hara and D. Grischkowsky  

E-Print Network [OSTI]

in the form of broadband (typically 0.05­2.5 THz), coherent, transform-limited pulses,5 this THz ra- diation­10 that are often strongly absorptive. On the other hand, many vi- sually opaque and, in fact, most dry, nonpolar types of THz imaging systems already exist, all having different meritorious properties. One such sys

425

D-dimensional Smorodinsky-Winternitz potential: Coherent state approach  

SciTech Connect (OSTI)

In this study, we construct the coherent states for a particle in the D-dimensional maximally superintegrable Smorodinsky-Winternitz potential. We, first, map the system into 2D harmonic oscillators, second, construct the coherent states of them by evaluating the transition amplitudes. Third, in the Cartesian and the hyperspherical coordinates, we find the coherent states and the stationary states of the original sytem by reduction.

Uenal, Nuri, E-mail: nuriunal@akdeniz.edu.tr [Akdeniz University, Department of Physics (Turkey)] [Akdeniz University, Department of Physics (Turkey)

2013-10-15T23:59:59.000Z

426

Multi-metastable states induced by the optical pump-probe process in terahertz quantum cascade lasers  

SciTech Connect (OSTI)

The optical pump-probe process in terahertz quantum cascade lasers is studied theoretically by using the open system simulation method. The emitter injection is considered and the charge neutrality in the active region is broken. We find that nonequilibrium oscillations may appear in the recovery processes. In particular, the formation of different equilibrium values of the population change after the periodic pulse pumping is observed clearly. Here, the phenomenon of multi-metastable states stems from the electron regulation by the emitter injection. Finally, we discuss the important impacts of the equilibrium stabilization time and obtain an in-depth understanding of the emitter injection.

Wang, F.; Guo, X. G., E-mail: xgguo@mail.sim.ac.cn; Wang, C.; Cao, J. C., E-mail: jccao@mail.sim.ac.cn [Key Laboratory of Terahertz Solid-State Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 865 Changning Road, Shanghai 200050 (China)

2014-07-14T23:59:59.000Z

427

The coordinate coherent states approach revisited  

SciTech Connect (OSTI)

We revisit the coordinate coherent states approach through two different quantization procedures in the quantum field theory on the noncommutative Minkowski plane. The first procedure, which is based on the normal commutation relation between an annihilation and creation operators, deduces that a point mass can be described by a Gaussian function instead of the usual Dirac delta function. However, we argue this specific quantization by adopting the canonical one (based on the canonical commutation relation between a field and its conjugate momentum) and show that a point mass should still be described by the Dirac delta function, which implies that the concept of point particles is still valid when we deal with the noncommutativity by following the coordinate coherent states approach. In order to investigate the dependence on quantization procedures, we apply the two quantization procedures to the Unruh effect and Hawking radiation and find that they give rise to significantly different results. Under the first quantization procedure, the Unruh temperature and Unruh spectrum are not deformed by noncommutativity, but the Hawking temperature is deformed by noncommutativity while the radiation specturm is untack. However, under the second quantization procedure, the Unruh temperature and Hawking temperature are untack but the both spectra are modified by an effective greybody (deformed) factor. - Highlights: Black-Right-Pointing-Pointer Suggest a canonical quantization in the coordinate coherent states approach. Black-Right-Pointing-Pointer Prove the validity of the concept of point particles. Black-Right-Pointing-Pointer Apply the canonical quantization to the Unruh effect and Hawking radiation. Black-Right-Pointing-Pointer Find no deformations in the Unruh temperature and Hawking temperature. Black-Right-Pointing-Pointer Provide the modified spectra of the Unruh effect and Hawking radiation.

Miao, Yan-Gang, E-mail: miaoyg@nankai.edu.cn; Zhang, Shao-Jun, E-mail: sjzhang@mail.nankai.edu.cn

2013-02-15T23:59:59.000Z

428

Coherent Carbon Cryogel-Ammonia Borane Nanocomposites for Improved...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Carbon Cryogel-Ammonia Borane Nanocomposites for Improved Hydrogen Storage. Coherent Carbon Cryogel-Ammonia Borane Nanocomposites for Improved Hydrogen Storage. Abstract: Ammonia...

429

The role of pump coherence in two-photon interferometry  

E-Print Network [OSTI]

We use a parametric down-conversion source pumped by a short coherence-length continuous-wave (CW) diode laser to perform two-photon interferometry in an intermediate regime between the more familiar Franson-type experiments with a long coherence-length pump laser, and the short pulsed pump "time-bin" experiments pioneered by Gisin's group. The use of a time-bin-like Mach-Zehnder interferometer in the CW pumping beam induces coherence between certain two-photon amplitudes, while the CW nature of the experiment prevents the elimination of remaining incoherent ones. The experimental results highlight the role of pump coherence in two-photon interferometry.

J. Liang; S. M. Hendrickson; T. B. Pittman

2010-12-20T23:59:59.000Z

430

Coherent Vibrational Dynamics and High-Resolution Nonlinear Spectrosco...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Vibrational Dynamics and High-Resolution Nonlinear Spectroscopy: A Comparison with the AirDMSO Liquid Interface. Coherent Vibrational Dynamics and High-Resolution Nonlinear...

431

On solving multistage stochastic programs with coherent risk ...  

E-Print Network [OSTI]

Aug 13, 2012 ... Abstract: We consider a class of multistage stochastic linear programs in which at each stage a coherent risk measure of future costs is to be ...

A. B. Philpott

2012-08-13T23:59:59.000Z

432

Coherent Transition Radiation in Askaryan radio detectors  

E-Print Network [OSTI]

We discuss the coherent transition radiation emitted by a macroscopic bunch of particles with a net charge traversing the boundary of two different media. The obtained expression is compared to the emission from a relativistically moving steady charge, as well the emission from a time-varying charge or current. As a first application, we discuss the transition radiation from high-energy cosmic-ray induced air showers hitting Earth's surface before the cascade has died out in the atmosphere. The induced emission gives rise to a radio signal which should be detectable in the currently operating Askaryan radio detectors built to search for the GZK neutrino flux.

de Vries, Krijn D; van Eijndhoven, Nick; Meures, Thomas; O'Murchadha, Aongus; Scholten, Olaf

2015-01-01T23:59:59.000Z

433

Self-Similar Modes of Coherent Diffusion  

E-Print Network [OSTI]

Self-similar solutions of the coherent diffusion equation are derived and measured. The set of real similarity solutions is generalized by the introduction of a nonuniform phase surface, based on the elegant Gaussian modes of optical diffraction. In an experiment of light storage in a gas of diffusing atoms, a complex initial condition is imprinted, and its diffusion dynamics is monitored. The self-similarity of both the amplitude and the phase pattern is demonstrated, and an algebraic decay associated with the mode order is measured. Notably, as opposed to a regular diffusion spreading, a self-similar contraction of a special subset of the solutions is predicted and observed.

O. Firstenberg; P. London; D. Yankelev; R. Pugatch; M. Shuker; N. Davidson

2010-08-16T23:59:59.000Z

434

COHERENT STRUCTURES IN PLASMA TURBULENCE: PERSISTENCE, INTERMITTENCY,  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation Proposed New Substation Sites Proposed Route BTRIC CNMSMethanol SteamNOTICE:PracticesCOHERENT

435

The Linac Coherent Light Source is  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear SecurityTensile Strain Switched Ferromagnetism in Layered NbS2 and NbSe2DifferentTheInforumLast W-79 WarheadCoherent

436

Optical coherence tomography guided dental drill  

DOE Patents [OSTI]

A dental drill that has one or multiple single mode fibers that can be used to image in the vicinity of the drill tip. It is valuable to image below the surface being drilled to minimize damage to vital or normal tissue. Identifying the boundary between decayed and normal enamel (or dentine) would reduce the removal of viable tissue, and identifying the nerve before getting too close with the drill could prevent nerve damage. By surrounding a drill with several optical fibers that can be used by an optical coherence domain reflectometry (OCDR) to image several millimeters ahead of the ablation surface will lead to a new and improved dental treatment device.

DaSilva, Luiz B. (Danville, CA); Colston, Jr., Bill W. (Livermore, CA); James, Dale L. (Tracy, CA)

2002-01-01T23:59:59.000Z

437

Terahertz dynamics of photogenerated carriers in ferromagnetic InGaMnAs G. A. Khodaparast, D. C. Larrabee, and J. Konoa)  

E-Print Network [OSTI]

response of InGaMnAs/InP by two-color pump­ probe spectroscopy, using an intense near-infrared beam used an intense picosecond pulse of near- infrared NIR radiation to create a large density of nonequilibrium carriers, which modifies the transmission and reflection of a delayed pulse of terahertz THz

Natelson, Douglas

438

Ultrafast electron cascades in semiconductors driven by intense femtosecond terahertz pulses H. Wen,1 M. Wiczer,3 and A. M. Lindenberg1,2  

E-Print Network [OSTI]

Ultrafast electron cascades in semiconductors driven by intense femtosecond terahertz pulses H. Wen processing. With wavelengths in the far infrared, near­ half-cycle THz pulses can be thought of as ultrafast,1 M. Wiczer,3 and A. M. Lindenberg1,2 1PULSE Institute, Stanford Linear Accelerator Center, Menlo

439

Terahertz absorption spectra of highly energetic chemicals E. J. Slingerlanda, M. K. Vallona, E. G. E. Jahngenb, R. H. Gilesa and T. M. Goyettea  

E-Print Network [OSTI]

Terahertz absorption spectra of highly energetic chemicals E. J. Slingerlanda, M. K. Vallona, E. G 01854 ABSTRACT Research into absorption spectra is useful for detecting chemicals in the field. Each theoretical models are available for predicting the absorption frequencies of a particular molecule

Massachusetts at Lowell, University of

440

Mon. Not. R. Astron. Soc. 416, 680688 (2011) doi:10.1111/j.1365-2966.2011.19084.x Herschel-Astrophysical Terahertz Large Area Survey: detection  

E-Print Network [OSTI]

-Astrophysical Terahertz Large Area Survey: detection of a far-infrared population around galaxy clusters K. E. K. Coppin,1, University of the Western Cape, Cape Town 7535, South Africa 16Department of Physics & Astronomy, The Open the detection of a significant excess in the surface density of far-infrared sources from the Herschel

Baes, Maarten

Note: This page contains sample records for the topic "high-power coherent terahertz" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


441

Time-resolved x-ray imaging of high-power laser-irradiated under-dense silica aerogels and agar foams  

SciTech Connect (OSTI)

This paper presents the results of experiments in which a high-power laser was used to irradiate low density (4 - 9 mg/cm{sup 3}) silica aerogel and agar foam targets. The laser-solid interaction and energy transport through the material were monitored with time-resolved imaging diagnostics, and the data show the production and propagation of an x-ray emission front in the plasma. The emission-front trajectory data are found to be in significant disagreement with detailed simulations, which predict a much more rapid heating of the cold material, and the data suggest that this discrepancy is not explainable by target inhomogeneities. Evidence suggests that energy transport into the cold material may be dominated by thermal conduction; however, no completely satisfactory explanation for the discrepancies is identified, and further experimental and theoretical research is necessary in order to resolve this important problem in laser-plasma interaction physics.

Koch, J.A.; Estabrook, K.G.; Bauer, J.D. [and others

1995-08-01T23:59:59.000Z

442

Catheter guided by optical coherence domain reflectometry  

DOE Patents [OSTI]

A guidance and viewing system based on multiplexed optical coherence domain reflectometry is incorporated into a catheter, endoscope, or other medical device to measure the location, thickness, and structure of the arterial walls or other intra-cavity regions at discrete points on the medical device during minimally invasive medical procedures. The information will be used both to guide the device through the body and to evaluate the tissue through which the device is being passed. Multiple optical fibers are situated along the circumference of the device. Light from the distal end of each fiber is directed onto the interior cavity walls via small diameter optics (such as gradient index lenses and mirrored corner cubes). Both forward viewing and side viewing fibers can be included. The light reflected or scattered from the cavity walls is then collected by the fibers and multiplexed at the proximal end to the sample arm of an optical low coherence reflectometer. The system may also be implemented in a nonmedical inspection device.

Everett, Matthew (Pleasanton, CA); Colston, Billy W. (Livermore, CA); Da Silva, Luiz B. (Danville, CA); Matthews, Dennis (Moss Beach, CA)

2002-01-01T23:59:59.000Z

443

Quantum process tomography with coherent states  

E-Print Network [OSTI]

We develop an enhanced technique for characterizing quantum optical processes based on probing unknown quantum processes only with coherent states. Our method substantially improves the original proposal [M. Lobino et al., Science 322, 563 (2008)], which uses a filtered Glauber-Sudarshan decomposition to determine the effect of the process on an arbitrary state. We introduce a new relation between the action of a general quantum process on coherent state inputs and its action on an arbitrary quantum state. This relation eliminates the need to invoke the Glauber-Sudarshan representation for states; hence it dramatically simplifies the task of process identification and removes a potential source of error. The new relation also enables straightforward extensions of the method to multi-mode and non-trace-preserving processes. We illustrate our formalism with several examples, in which we derive analytic representations of several fundamental quantum optical processes in the Fock basis. In particular, we introduce photon-number cutoff as a reasonable physical resource limitation and address resource vs accuracy trade-off in practical applications. We show that the accuracy of process estimation scales inversely with the square root of photon-number cutoff.

Saleh Rahimi-Keshari; Artur Scherer; Ady Mann; Ali T. Rezakhani; A. I. Lvovsky; Barry C. Sanders

2010-09-17T23:59:59.000Z

444

High-frequency response and the possibilities of frequency-tunable narrow-band terahertz amplification in resonant tunneling nanostructures  

SciTech Connect (OSTI)

The characteristics of the high-frequency response of single- and double-well resonant tunneling structures in a dc electric field are investigated on the basis of the numerical solution of a time-dependent Schroedinger equation with open boundary conditions. The frequency dependence of the real part of high frequency conductivity (high-frequency response) in In{sub 0.53}Ga{sub 0.47}As/AlAs/InP structures is analyzed in detail for various values of the dc voltage V{sub dc} in the negative differential resistance (NDR) region. It is shown that double-well three-barrier structures are promising for the design of terahertz-band oscillators. The presence of two resonant states with close energies in such structures leads to a resonant (in frequency) response whose frequency is determined by the energy difference between these levels and can be controlled by varying the parameters of the structure. It is shown that, in principle, such structures admit narrow-band amplification, tuning of the amplification frequency, and a fine control of the amplification (oscillation) frequency in a wide range of terahertz frequencies by varying a dc electric voltage applied to the structure. Starting from a certain width of the central intermediate barrier in double-well structures, one can observe a collapse of resonances, where the structure behaves like a single-well system. This phenomenon imposes a lower limit on the oscillation frequency in three-barrier resonant tunneling structures.

Kapaev, V. V., E-mail: kapaev@sci.lebedev.ru; Kopaev, Yu. V.; Savinov, S. A.; Murzin, V. N. [Russian Academy of Sciences, Lebedev Physical Institute (Russian Federation)] [Russian Academy of Sciences, Lebedev Physical Institute (Russian Federation)

2013-03-15T23:59:59.000Z

445

Robust time-varying multivariate coherence estimation: Application to electroencephalogram recordings during general anesthesia  

E-Print Network [OSTI]

Coherence analysis characterizes frequency-dependent covariance between signals, and is useful for multivariate oscillatory data often encountered in neuroscience. The global coherence provides a summary of coherent behavior ...

Brown, Emery N.

446

The Quasi-Coherent Oscillations of SS Cygni  

E-Print Network [OSTI]

Properties of the quasi-coherent oscillations in the extreme ultraviolet (EUV) flux of the dwarf nova SS Cygni are described, with emphasis on (1) the scaling between the period of the oscillation and the EUV flux and (2) the mean power spectra and waveforms. In addition, a quasi-coherent oscillation at \

Christopher W. Mauche

1996-08-22T23:59:59.000Z

447

Optical quantum swapping in a coherent atomic medium  

E-Print Network [OSTI]

We propose to realize a passive optical quantum swapping device which allows for the exchange of the quantum fluctuations of two bright optical fields interacting with a coherent atomic medium in an optical cavity. The device is based on a quantum interference process between the fields within the cavity bandwidth arising from coherent population trapping in the atomic medium.

Aurelien Dantan

2011-10-03T23:59:59.000Z

448

Mode coherence at megameter ranges in the North Pacific Ocean  

E-Print Network [OSTI]

Mode coherence at megameter ranges in the North Pacific Ocean Kathleen E. Wage, Matthew A and the Acoustical Society of America. #12;Mode coherence at megameter ranges in the North Pacific Ocean Kathleen E Thermometry of Ocean Climate ATOC and Alternate Source Test AST experiments. Vertical line arrays at Hawaii

Wage, Kathleen

449

Modular Quantum Memories Using Passive Linear Optics and Coherent Feedback  

E-Print Network [OSTI]

Modular Quantum Memories Using Passive Linear Optics and Coherent Feedback Hendra I. Nurdin photon pulsed optical field has a conceptually simple modular realization using only passive linear optics and coherent feedback. We exploit the idea that two decaying optical cavities can be coupled

450

Coherent Quantum-Noise Cancellation for Optomechanical Sensors  

E-Print Network [OSTI]

Using a flowchart representation of quantum optomechanical dynamics, we design coherent quantum-noise-cancellation schemes that can eliminate the back-action noise induced by radiation pressure at all frequencies and thus overcome the standard quantum limit of force sensing. The proposed schemes can be regarded as novel examples of coherent feedforward quantum control.

Mankei Tsang; Carlton M. Caves

2010-08-17T23:59:59.000Z

451

Unsupervised extraction of coherent regions for image based rendering  

E-Print Network [OSTI]

Unsupervised extraction of coherent regions for image based rendering Jesse Berent and Pier Luigi, UK {jesse.berent, p.dragotti}@imperial.ac.uk Abstract Image based rendering using undersampled light information. In pop-up light field rendering [18], the scene is segmented into coherent layers, usually

Dragotti, Pier Luigi

452

Coherent spinor dynamics in a spin-1 Bose condensate  

E-Print Network [OSTI]

, for example, a Bose­Einstein condensate or a degenerate Fermi gas, the phase space accessible to low of coherent spin-changing collisions in a gas of spin-1 bosons. Starting with condensates occupying two spin of the gas, although it does not change the nature of the coherence of the condensate--indeed it has been

Loss, Daniel

453

Conditions for two-photon interference with coherent pulses  

E-Print Network [OSTI]

We study the conditions for two-photon classical interference with coherent pulses. We find that the temporal overlap between optical pulses is not required for interference However, coherence within the same inputs is found to be essential for the interference.

Yong-Su Kim; Oliver Slattery; Paulina S. Kuo; Xiao Tang

2013-06-27T23:59:59.000Z

454

Generation of Coherent Institute for Perception Research (IPO)  

E-Print Network [OSTI]

Generation of Coherent Monologues Jan Odijk Institute for Perception Research (IPO) P.O.Box 513 for generating coherent texts is de- scribed. In this method only local conditions associated with sentences any form of planning and it concentrates on maximizing the amount of variation of the texts generated

Theune, Mariët

455

Quantum coherence, time-translation symmetry and thermodynamics  

E-Print Network [OSTI]

The first law of thermodynamics imposes not just a constraint on the energy-content of systems in extreme quantum regimes, but also symmetry-constraints related to the thermodynamic processing of quantum coherence. We show that this thermodynamic symmetry decomposes any quantum state into mode operators that quantify the coherence present in the state. We then establish general upper and lower bounds for the evolution of quantum coherence under arbitrary thermal operations, valid for any temperature. We identify primitive coherence manipulations and show that the transfer of coherence between energy levels manifests irreversibility not captured by free energy. Moreover, the recently developed thermo-majorization relations on block-diagonal quantum states are observed to be special cases of this symmetry analysis.

Matteo Lostaglio; Kamil Korzekwa; David Jennings; Terry Rudolph

2015-04-13T23:59:59.000Z

456

E-Print Network 3.0 - adaptive-optics optical coherence Sample...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

optics optical coherence Search Powered by Explorit Topic List Advanced Search Sample search results for: adaptive-optics optical coherence Page: << < 1 2 3 4 5 > >> 1 NW...

457

Swept source optical coherence microscopy for pathological assessment of cancerous tissues  

E-Print Network [OSTI]

Optical coherence microscopy (OCM) combines optical coherence tomography (OCT) with confocal microscopy and enables depth resolved visualization of biological specimens with cellular resolution. OCM offers a suitable ...

Ahsen, Osman Oguz

2013-01-01T23:59:59.000Z

458

Atmospheric rivers as Lagrangian coherent structures  

E-Print Network [OSTI]

We show that filamentous Atmospheric Rivers (ARs) over the Northern Atlantic Ocean are closely linked to attracting Lagrangian Coherent Structures (LCSs) in the large scale wind field. LCSs represent lines of attraction in the evolving flow with a significant impact on all passive tracers. Using Finite-Time Lyapunov Exponents (FTLE), we extract LCSs from a two-dimensional flow derived from water vapor flux of atmospheric reanalysis data and compare them to the three-dimensional LCS obtained from the wind flow. We correlate the typical filamentous water vapor patterns of ARs with LCSs and find that LCSs bound the filaments on the back side. Passive advective transport of water vapor from tropical latitudes is potentially possible.

Garaboa, Daniel; Huhn, Florian; Perez-Muñuzuri, Vicente

2015-01-01T23:59:59.000Z

459

Unambiguous coherent state identification: Searching a quantum database  

E-Print Network [OSTI]

We consider an unambiguous identification of an unknown coherent state with one of two unknown coherent reference states. Specifically, we consider two modes of an electromagnetic field prepared in unknown coherent states alpha_1 and alpha_2, respectively. The third mode is prepared either in the state alpha_1 or in the state alpha_2. The task is to identify (unambiguously) which of the two modes are in the same state. We present a scheme consisting of three beamsplitters capable to perform this task. Although we don't prove the optimality, we show that the performance of the proposed setup is better than the generalization of the optimal measurement known for a finite-dimensional case. We show that a single beamsplitter is capable to perform an unambiguous quantum state comparison for coherent states optimally. Finally we propose an experimental setup consisting of 2N-1 beamsplitters for unambiguous identification among N unknown coherent states. This setup can be considered as a search in a quantum database. The elements of the database are unknown coherent states encoded in different modes of an electromagnetic field. The task is to specify the two modes that are excited in the same, though unknown, coherent state.

Michal Sedlak; Mario Ziman; Ondrej Pribyla; Vladimir Buzek; Mark Hillery

2007-07-23T23:59:59.000Z

460

Effect of oxygen incorporation on the structure and elasticity of Ti-Al-O-N coatings synthesized by cathodic arc and high power pulsed magnetron sputtering  

SciTech Connect (OSTI)

Ti-Al-O-N coatings were synthesized by cathodic arc and high power pulsed magnetron sputtering. The chemical composition of the coatings was determined by means of elastic recoil detection analysis and energy dispersive X-ray spectroscopy. The effect of oxygen incorporation on the stress-free lattice parameters and Young's moduli of Ti-Al-O-N coatings was investigated by X-ray diffraction and nanoindentation, respectively. As nitrogen is substituted by oxygen, implications for the charge balance may be expected. A reduction in equilibrium volume with increasing O concentration is identified by X-ray diffraction and density functional theory calculations of Ti-Al-O-N supercells reveal the concomitant formation of metal vacancies. Hence, the oxygen incorporation-induced formation of metal vacancies enables charge balancing. Furthermore, nanoindentation experiments reveal a decrease in elastic modulus with increasing O concentration. Based on ab initio data, two causes can be identified for this: First, the metal vacancy-induced reduction in elasticity; and second, the formation of, compared to the corresponding metal nitride bonds, relatively weak Ti-O and Al-O bonds.

Hans, M., E-mail: hans@mch.rwth-aachen.de; Baben, M. to; Music, D.; Ebenhöch, J.; Schneider, J. M. [Materials Chemistry, RWTH Aachen University, Kopernikusstr. 10, D-52074 Aachen (Germany); Primetzhofer, D. [Department of Physics and Astronomy, Uppsala University, Lägerhyddsvägen 1, S-75120 Uppsala (Sweden); Kurapov, D.; Arndt, M.; Rudigier, H. [Oerlikon Balzers Coating AG, Iramali 18, LI-9496 Balzers, Principality of Liechtenstein (Liechtenstein)

2014-09-07T23:59:59.000Z

Note: This page contains sample records for the topic "high-power coherent terahertz" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


461

Atomic Beam Merging and Suppression of Alkali Contaminants in Multi Body High Power Targets: Design and Test of Target and Ion Source Prototypes at ISOLDE  

E-Print Network [OSTI]

The next generation of high power ISOL-facilities will deliver intense and pure radioactive ion beams. Two key issues of developments mandatory for the forthcoming generation of ISOL target-ion source units are assessed and demonstrated in this thesis. The design and production of target and ion-source prototypes is described and dedicated measurements at ISOLDE-CERN of their radioisotope yields are analyzed. The purity of short lived or rare radioisotopes suffer from isobaric contaminants, notably alkalis which are highly volatile and easily ionized elements. Therefore, relying on their chemical nature, temperature controlled transfer lines were equipped with a tube of quartz that aimed at trapping these unwanted elements before they reached the ion source. The successful application yields high alkali-suppression factors for several elements (ie: 80, 82mRb, 126, 142Cs, 8Li, 46K, 25Na, 114In, 77Ga, 95, 96Sr) for quartz temperatures between 300ºC and 1100ºC. The enthalpies of adsorption on quartz were measu...

Bouquerel, Elian J A; Lettry, J; Stora, T

2009-01-01T23:59:59.000Z

462

Power combination of two phase-locked high power microwave beams from a new coaxial microwave source based on dual beams  

SciTech Connect (OSTI)

The new coaxial high power microwave source based on dual beams has demonstrated two phase-locked output microwave beams generated by its two sub-sources. In order to achieve a single higher output power, we present a three-port waveguide-based power combiner to combine the two microwave beams. Particle-in-cell simulation results show that when the diode voltage is 675?kV and the guiding magnetic field is 0.8?T, a combined microwave with an average power of about 4.0?GW and a frequency of 9.74 GHz is generated; the corresponding power conversion efficiency is 29%. The combination effect of the combiner is further validated in the diode voltage range from 675?kV to 755?kV as well as in the pulse regime. The simulations indicate that the maximum surface axial electric field strength of the electrodynamic structure is 720?kV/cm, which is relatively low corresponding to an output power of 4.0?GW. The stable combined output suggests the probability of long-pulse operation for the combined source.

Li, Yangmei; Zhang, Xiaoping, E-mail: plinafly@163.com; Zhang, Jiande; Dang, Fangchao; Yan, Xiaolu [College of Optoelectric Science and Engineering, National University of Defense Technology, Changsha 410073 (China)

2014-10-15T23:59:59.000Z

463

Coherent structures in compressible free-shear-layer flows  

SciTech Connect (OSTI)

Large scale coherent structures are intrinsic fluid mechanical characteristics of all free-shear flows, from incompressible to compressible, and laminar to fully turbulent. These quasi-periodic fluid structures, eddies of size comparable to the thickness of the shear layer, dominate the mixing process at the free-shear interface. As a result, large scale coherent structures greatly influence the operation and efficiency of many important commercial and defense technologies. Large scale coherent structures have been studied here in a research program that combines a synergistic blend of experiment, direct numerical simulation, and analysis. This report summarizes the work completed for this Sandia Laboratory-Directed Research and Development (LDRD) project.

Aeschliman, D.P.; Baty, R.S. [Sandia National Labs., Albuquerque, NM (United States). Engineering Sciences Center; Kennedy, C.A.; Chen, J.H. [Sandia National Labs., Livermore, CA (United States). Combustion and Physical Sciences Center

1997-08-01T23:59:59.000Z

464

Origin of Long Lived Coherences in Light-Harvesting Complexes  

E-Print Network [OSTI]

A vibronic exciton model is developed to investigate the origin of long lived coherences in light-harvesting complexes. Using experimentally determined parameters and uncorrelated site energy fluctuations, the model predicts oscillations in the nonlinear spectra of the Fenna-Matthews-Olson (FMO) complex with a dephasing time of 1.3 ps at 77 K. These oscillations correspond to the coherent superposition of vibronic exciton states with dominant contributions from vibrational excitations on the same pigment. Purely electronic coherences are found to decay on a 200 fs timescale.

Niklas Christensson; Harald F. Kauffmann; Tonu Pullerits; Tomas Mancal

2012-01-30T23:59:59.000Z

465

Coherent state of a weakly interacting ultracold Fermi gas  

E-Print Network [OSTI]

We examine the weakly interacting atoms in an ultracold Fermi gas leading to a state of macroscopic coherence, from a theoretical perspective. It has been shown that this state can be described as a fermionic coherent state. These coherent states are the eigenstates of fermionic annihilation operators, the eigenvalues being anti-commuting numbers or Grassmann numbers. By exploiting the simple rules of Grassmann algebra and a close kinship between relations evaluated for more familiar bosonic fields and those for fermionic fields, we derive the thermodynamic limit, the spontaneous symmetry breaking and the quasi-particle spectrum of the fermionic system.

Arnab Ghosh; Sudarson Sekhar Sinha; Deb Shankar Ray

2013-04-04T23:59:59.000Z

466

Coherent excitation of a single atom to a Rydberg state  

SciTech Connect (OSTI)

We present the coherent excitation of a single Rubidium atom to the Rydberg state 58d{sub 3/2} using a two-photon transition. The experimental setup is described in detail, as are experimental techniques and procedures. The coherence of the excitation is revealed by observing Rabi oscillations between ground and Rydberg states of the atom. We analyze the observed oscillations in detail and compare them to numerical simulations which include imperfections of our experimental system. Strategies for future improvements on the coherent manipulation of a single atom in our settings are given.

Miroshnychenko, Y.; Gaeetan, A.; Evellin, C.; Grangier, P.; Wilk, T.; Browaeys, A. [Laboratoire Charles Fabry, Institut d'Optique, Centre National de la Recherche Scientifique, Universite Paris-Sud, Campus Polytechnique, RD 128, F-91127 Palaiseau CEDEX (France); Comparat, D.; Pillet, P. [Laboratoire Aime Cotton, Centre National de la Recherche Scientifique, Universite Paris-Sud, Batiment 505, Campus d'Orsay, F-91405 Orsay CEDEX (France)

2010-07-15T23:59:59.000Z

467

Design of interferometer system for Keda Torus eXperiment using terahertz solid-state diode sources  

SciTech Connect (OSTI)

A solid-state source based terahertz (THz) interferometer diagnostic system has been designed and characterized for the Keda Torus eXperiment (KTX). The THz interferometer utilizes the planar diodes based frequency multiplier (X48) to provide the probing beam at fixed frequency 0.650 THz, and local oscillator is provided by an independent solid-state diode source with tunable frequency (0.650 THz +/? 10 MHz). Both solid-state sources have approximately 1 mW power. The planar-diode mixers optimized for high sensitivity, ?750 mV/mW, are used in the heterodyne detection system, which permits multichannel interferometer on KTX with a low phase noise. A sensitivity of {sub min} = 4.5 × 10{sup 16} m{sup ?2} and a temporal resolution of 0.2 ?s have been achieved during the initial bench test.

Xie, Jinlin, E-mail: jlxie@ustc.edu.cn; Wang, Haibo; Li, Hong; Lan, Tao; Liu, Adi; Liu, Wandong; Yu, Changxuan [School of Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China); Ding, Weixing [School of Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China); University of California-Los Angeles, P. O. Box 957099, Los Angeles, California 90095-7099 (United States)

2014-11-15T23:59:59.000Z

468

Strong enhancement of terahertz emission from GaAs in InAs/GaAs quantum dot structures  

SciTech Connect (OSTI)

We report on the intense terahertz emission from InAs/GaAs quantum dot (QD) structures grown by molecular beam epitaxy. Results reveal that the QD sample emission was as high as 70% of that of a p-type InAs wafer, the most intense semiconductor emitter to date. Excitation wavelength studies showed that the emission was due to absorption in strained undoped GaAs, and corresponds to a two order-of-magnitude enhancement. Moreover, it was found that multilayer QDs emit more strongly compared with a single layer QD sample. At present, we ascribe the intense radiation to huge strain fields at the InAs/GaAs interface.

Estacio, Elmer; Pham, Minh Hong; Takatori, Satoru; Cadatal-Raduban, Marilou; Nakazato, Tomoharu; Shimizu, Toshihiko; Sarukura, Nobuhiko [Institute of Laser Engineering, Osaka University, 2-6 Yamadaoka, Suita, Osaka 565-0871 (Japan); Somintac, Armando; Defensor, Michael; Awitan, Fritz Christian B.; Jaculbia, Rafael B.; Salvador, Arnel [National Institute of Physics, University of the Philippines, Diliman, Quezon City 1101 (Philippines); Garcia, Alipio [Department of Physical Sciences, University of the Philippines, Baguio City 2600 (Philippines)

2009-06-08T23:59:59.000Z

469

Comparison of gold- and graphene-based resonant nanostructures for terahertz metamaterials and an ultrathin graphene-based modulator  

SciTech Connect (OSTI)

Graphene exhibits unique material properties, and in electromagnetic wave technology it raises the prospect of devices miniaturized down to the atomic length scale. Here we study split-ring resonator metamaterials made from graphene and we compare them to gold-based metamaterials. We find that graphene's huge reactive response derived from its large kinetic inductance allows for deeply subwavelength resonances, although its resonance strength is reduced due to higher dissipative loss damping and smaller dipole coupling. Nevertheless, tightly stacked graphene rings may provide for negative permeability and the electric dipole resonance of graphene meta-atoms turns out to be surprisingly strong. Based on these findings, we present a terahertz modulator based on a metamaterial with a multilayer stack of alternating patterned graphene sheets separated by dielectric spacers. Neighboring graphene flakes are biased against each other, resulting in modulation depths of over 75% at a transmission level of around 90%.

Shen, Nian-Hai [Ames Laboratory; Tassin, Philippe [Ames Laboratory; Koschny, Thomas [Ames Laboratory; Soukoulis, Costas M [Ames Laboratory

2014-09-01T23:59:59.000Z

470

E-Print Network 3.0 - assisted laser ionization Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Summary: of a high power pulsed far-infrared laser. Furthermore, impurity ionization with terahertz radiation can... of ionization capture processes due to the Poole-Frenkel...

471

Atmospheric Lagrangian coherent structures considering unresolved turbulence and forecast uncertainty  

E-Print Network [OSTI]

Atmospheric Lagrangian coherent structures considering unresolved turbulence and forecast structures Stochastic trajectory Stochastic FTLE field Ensemble forecasting Uncertainty analysis a b s t r of the forecast FTLE fields is analyzed using ensemble forecasting. Unavoidable errors of the forecast velocity

Ross, Shane

472

Temperature-dependent coherent oscillation in photorefractive relaxor strontium barium  

E-Print Network [OSTI]

Temperature-dependent coherent oscillation in photorefractive relaxor strontium barium niobate M of the photorefractive light-induced scattering (beam fanning) in Sr0.61Ba0.39Nb2O6 (strontium barium niobate) doped

Osnabrück, Universität

473

Coherence characterization with a superconducting flux qubit through NMR approaches  

E-Print Network [OSTI]

This thesis discusses a series of experimental studies that investigate the coherence properties of a superconducting persistent-current or flux qubit, a promising candidate for developing a scalable quantum processor. A ...

Yan, Fei, Ph. D. Massachusetts Institute of Technology

2013-01-01T23:59:59.000Z

474

Low-coherent WDM reflectometry for accurate fiber length monitoring  

E-Print Network [OSTI]

A fiber-optic low-coherent reflectometer was developed to accurately monitor fiber length variation. A large length-coverage range was obtained by using a fiber Bragg grating array in a wavelength-division-multiplexing ...

Hui, Rongqing; Thomas, J.; Allen, Christopher Thomas; Fu, B.; Gao, S.

2003-01-01T23:59:59.000Z

475

Magnetism studies using resonant, coherent, x-ray scattering...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Magnetism studies using resonant, coherent, x-ray scattering Monday, September 10, 2012 - 10:00am SLAC, Bldg. 137, Room 226 Keoki Seu Seminar: With the advent of free electron...

476

Water Window Ptychographic Imaging with Characterized Coherent X-rays  

E-Print Network [OSTI]

We report on a ptychographical coherent diffractive imaging experiment in the water window with focused soft X-rays at $500~\\mathrm{eV}$. An X-ray beam with high degree of coherence was selected for ptychography at the P04 beamline of the PETRA III synchrotron radiation source. We measured the beam coherence with the newly developed non-redundant array method. A pinhole $2.6~\\mathrm{\\mu m}$ in size selected the coherent part of the beam and was used for ptychographic measurements of a lithographically manufactured test sample and fossil diatom. The achieved resolution was $53~\\mathrm{nm}$ for the test sample and only limited by the size of the detector. The diatom was imaged at a resolution better than $90~\\mathrm{nm}$.

Rose, Max; Dzhigaev, Dmitry; Gorobtsov, Oleg; Senkbeil, Tobias; von Gundlach, Andreas; Gorniak, Thomas; Shabalin, Anatoly; Viefhaus, Jens; Rosenhahn, Axel; Vartanyants, Ivan

2015-01-01T23:59:59.000Z

477

Development of Molecular Contrast in Coherence Domain Optical Imaging  

E-Print Network [OSTI]

. This technique could be used potentially as a clinical tool for diagnosing different progression stages of melanoma. This technique could also be applied to differentiate other mixed chromophores. Second harmonic optical coherence tomography (SHOCT) is non...

Wan, Qiujie

2012-02-14T23:59:59.000Z

478

Optimizing directory-based cache coherence on the RAW architecture  

E-Print Network [OSTI]

Caches help reduce the effect of long-latency memory requests, by providing a high speed data-path to local memory. However, in multi-processor systems utilizing shared memory, cache coherence protocols are necessary to ...

Ramaswamy, Satish

2005-01-01T23:59:59.000Z

479

Doppler optical coherence microscopy for studies of cochlear mechanics  

E-Print Network [OSTI]

The possibility of measuring subnanometer motions with micron scale spatial resolution in the intact mammalian cochlea using Doppler optical coherence microscopy (DOCM) is demonstrated. A novel DOCM system is described ...

Hong, Stanley S.

480

The minimum-uncertainty coherent states for Landau levels  

SciTech Connect (OSTI)

The Glauber minimum-uncertainty coherent states with two variables for Landau levels, based on the representation of Weyl-Heisenberg algebra by two different modes, have been studied about four decades ago. Here, we introduce new two-variable coherent states with minimum uncertainty relationship for Landau levels in three different methods: the infinite unitary representation of su(1, 1) is realized in two different methods, first, by consecutive levels with the same energy gaps and also with the same value for z-angular momentum quantum number, then, by shifting z-angular momentum mode number by two units while the energy level remaining the same. Besides, for su(2), whether by lowest Landau levels or Landau levels with lowest z-angular momentum, just one finite unitary representation is introduced. Having constructed the generalized Klauder-Perelomov coherent states, for any of the three representations, we obtain their Glauber coherency by displacement operator of Weyl-Heisenberg algebra.

Dehghani, A. [Physics Department, Payame Noor University, P. O. Box 19395-4697 Tehran (Iran, Islamic Republic of); Fakhri, H. [Department of Theoretical Physics and Astrophysics, Faculty of Physics, University of Tabriz, P. O. Box 51666-16471 Tabriz (Iran, Islamic Republic of); Mojaveri, B. [Department of Physics, Azarbaijan Shahid Madani University, P. O. Box 51745-406 Tabriz (Iran, Islamic Republic of)

2012-12-15T23:59:59.000Z

Note: This page contains sample records for the topic "high-power coherent terahertz" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


481

Documentation Integrity for Safety-Critical Applications: The COHERE Project  

E-Print Network [OSTI]

. Keywords Authoring interface, documentation integrity, consistency 1. INTRODUCTION This paper reportsDocumentation Integrity for Safety-Critical Applications: The COHERE Project David G. Novick-critical systems. Following a set of documentation integrity maxims, the project developed two generations

Novick, David G.

482

Ecological coherence of Natura2000 protected areas in Scotland   

E-Print Network [OSTI]

important for ecological coherence (representivity, replication, patch sizes and shapes, and connectivity). In this study, a method is presented that addresses all of the above criteria for three main Annex I habitats in Scotland (Caledonian woodland, Tilio...

Winstrup, Mie

2012-11-29T23:59:59.000Z

483

Computational imaging for 3D phase and coherence retrieval |...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Computational imaging for 3D phase and coherence retrieval Wednesday, December 10, 2014 - 3:00pm SLAC, Redtail Hawk Conference Room 108A Speaker: Laura Waller (UC Berkeley) Program...

484

Coherent feedback that beats all measurement-based feedback protocols  

E-Print Network [OSTI]

We show that when the speed of control is bounded, there is a widely applicable minimal-time control problem for which a coherent feedback protocol is optimal, and is faster than all measurement-based feedback protocols, ...

Jacobs, Kurt

485

Finite blocklength analysis of the MISO Coherent Block Fading Channel  

E-Print Network [OSTI]

The Coherent MISO Block Fading Channel is a wireless communication channel model in which the transmitter has access to multiple antennas while the receiver has access to one. This model is becoming increasingly important ...

Collins, Austin Daniel

2014-01-01T23:59:59.000Z

486

Quantum Coherence Effects in Novel Quantum Optical Systems  

E-Print Network [OSTI]

and find interesting applications. We show that quantum coherence can lead to transient Raman lasing and lasing without inversion in short wavelength spectral regions--extreme ultraviolet and x-ray--without the requirement of incoherent pumping. For example...

Sete, Eyob Alebachew

2012-10-19T23:59:59.000Z

487

Quantum coherence, time-translation symmetry and thermodynamics  

E-Print Network [OSTI]

The first law of thermodynamics imposes not just a constraint on the energy-content of systems in extreme quantum regimes, but also symmetry-constraints related to the thermodynamic processing of quantum coherence. Harmonic analysis allows any density operator to be decomposed in terms of mode operators which quantify the coherence present in a state in a natural way. We establish upper and lower bounds for the evolution of such modes under arbitrary thermal operations, and analyse primitive coherence manipulations. Well-studied thermo-majorization relations on block-diagonal quantum states correspond to constraints only on the zero-mode of a state, governing energy transfers. A complete set of constraints for non-zero modes, governing coherence transfers, is at present unknown, but these modes are found to display similar irreversibility, which demands greater study.

Matteo Lostaglio; Kamil Korzekwa; David Jennings; Terry Rudolph

2014-10-16T23:59:59.000Z

488

Coherent radar ice thickness measurements over the Greenland ice sheet  

E-Print Network [OSTI]

We developed two 150-MHz coherent radar depth sounders for ice thickness measurements over the Greenland ice sheet. We developed one of these using connectorized components and the other using radio frequency integrated circuits (RFICs). Both...

Gogineni, S. Prasad; Tammana, Dilip; Braaten, David A.; Leuschen, C.; Legarsky, J.; Kanagaratnam, P.; Stiles, J.; Allen, C.; Jezek, K.; Akins, T.

2001-12-27T23:59:59.000Z

489

anatomical optical coherence: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Ivan; Wang, Yimin; Chen, Zhongping 2004-01-01 3 Coherent Communication with Linear Optics Quantum Physics (arXiv) Summary: We show how to implement several continuous-variable...

490

Studying coherence in ultra-cold atomic gases  

E-Print Network [OSTI]

This thesis will discuss the study of coherence properties of ultra-cold atomic gases. The atomic systems investigated include a thermal cloud of atoms, a Bose-Einstein condensate and a fermion pair condensate. In each ...

Miller, Daniel E. (Daniel Edward)

2007-01-01T23:59:59.000Z

491

Technical Report: Final project report for Terahertz Spectroscopy of Complex Matter  

SciTech Connect (OSTI)

This project designed characterization techniques for thin films of complex matter and other materials in the terahertz spectral region extending from approximately 100 GHz to 4000 GHz (4 THz) midway between radio waves and light. THz has traditionally been a difficult region of the spectrum in which to conduct spectroscopic measurements. The “THz gap” arises from the nature of the sources and detectors used in spectroscopy both at the optical (high frequency) side and electronic (low frequency) side of the gap. To deal with the extremely rapid oscillations of the electric field in this frequency region this research project adapted techniques from both the electronics and optics technologies by fabricating microscopic antennas and driving them with short optical pulses. This research technique creates nearly single cycle pulses with extremely broad spectral bandwidth that are able to cover the THz spectral range with a single measurement. The technique of THz time domain spectroscopy (THz-TDS) has seen increasing use and acceptance in laboratories over the past fifteen years. However significant technical challenges remain in order to allow THz-TDS to be applied to measurement of solid materials, particularly thin films and complex matter. This project focused on the development and adaptation of time domain THz measurement techniques to investigate the electronic properties of complex matter in the terahertz frequency region from 25 GHz to beyond 5 THz (<1 inv. cm to >165 inv. cm). This project pursued multiple tracks in adapting THz Time Domain Spectroscopy (THz-TDS) to measurement of complex matter. The first, and most important, is development of a reliable methods to characterize the complex dielectric constant of thin films with high accuracy when the wavelength of the THz radiation is much longer than the thickness of the film. We have pursued several techniques for measurement of thin films. The most promising of these are waveguide spectroscopy and THz interferometry. Since THz spectroscopy measures the changes of the transmitted spectra, any noise on the THz signal contributes to measurement errors. The dynamic range—defined as the RMS noise of the THz detector compared to the peak THz signal—of THz spectroscopy using photoconductive antennas is extremely high, typically over 10,000. However the precision with which spectroscopic data can be measured is limited by the noise on the laser source which is typically 0.1% to 1%. For low values of the sample absorbance and for values of optical thickness less than approximately 0.01, the change in transmission approaches the measurement accuracy. The sample refractive index can be measured with better accuracy since the index causes a temporal shift of the THz pulse by an amount time shift of nd/c where n is the refractive index, d the sample thickness, and c the speed of light. Time shifts of tens of femtoseconds can generally be resolved so that index-thickness values of nd > ten microns can be accurately measured. Waveguide spectroscopy is a way to increase the path length in thin film by several orders of magnitude, and thus have a large interaction length even when the film is much less than a wavelength in thickness. Film thicknesses of 10’s of nm have been measured. THz interferometry cancels out many of the noise sources of THz spectroscopy and can thus result in measurements of films of several hundred nm in thickness and is additionally suitable for optical pump, THz probe spectroscopic techniques. A large amount of additional work was performed in support of the main project direction or to explore promising alternative avenues for research. This report discussed work on the the confinement of low density species for measurement of nanogram or picogram quantities of material. Whispering gallery mode resonators to achieve long path lengths were also investigated as were imaging techniques for sub-wavelength imaging of thin films. The report concludes with a report on investigations of fundamental issues in THz beam propagation and coupli

R. A. Cheville; D. R. Grischkowsky

2007-02-08T23:59:59.000Z

492

Terahertz generation and detection with InGaAs-based large-area photoconductive devices excited at 1.55??m  

SciTech Connect (OSTI)

We report on scalable large-area terahertz emitters and detectors based on In{sub 0.53}Ga{sub 0.47}As/In{sub 0.52}Al{sub 0.48}As heterostructures for excitation with 1.55??m radiation. Different geometries involving three different electrode gap sizes are compared with respect to terahertz (THz) emission, bias field distribution, and Joule heating. The field distribution becomes more favorable for THz emission as gap size increases, while Joule heating exhibits the opposite dependence. Devices with three different gap sizes, namely 3??m, 5??m, and 7.5??m, have been investigated experimentally, the emitter with a gap size of 7.5??m showed the best performance. The scalable devices are furthermore employed as detectors. The scalable electrode geometry enables spatially integrated detection, which is attractive for specific applications, e.g., where an unfocused THz beam has to be used.

Xu, Ming [Applied Physics Department, Xi'an University of Technology, No. 58 Yanxiang Road, Xi'an 710054 (China) [Applied Physics Department, Xi'an University of Technology, No. 58 Yanxiang Road, Xi'an 710054 (China); Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstraße 400, 01328 Dresden (Germany); Mittendorff, Martin; Helm, Manfred [Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstraße 400, 01328 Dresden (Germany) [Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstraße 400, 01328 Dresden (Germany); Technische Universität Dresden, 01062 Dresden (Germany); Dietz, Roman J. B.; Künzel, Harald; Sartorius, Bernd; Göbel, Thorsten [Fraunhofer Institute for Telecommunication, Heinrich-Hertz-Institute, Einsteinufer 37, 10587 Berlin (Germany)] [Fraunhofer Institute for Telecommunication, Heinrich-Hertz-Institute, Einsteinufer 37, 10587 Berlin (Germany); Schneider, Harald; Winnerl, Stephan [Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstraße 400, 01328 Dresden (Germany)] [Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstraße 400, 01328 Dresden (Germany)

2013-12-16T23:59:59.000Z

493

Inversionless amplification in semiconductor nanostructures: A way to create a frequency-tunable laser of far-infrared and terahertz radiation  

SciTech Connect (OSTI)

A scheme of a far-infrared and terahertz amplifier or laser based on a semiconductor nanostructure, consisting of a superlattice of double quantum wells of a certain design placed into a planar metal waveguide and pumped by a CO{sub 2} laser, is suggested. The structure operation is based on the inversionless mechanism of electromagnetic field amplification, which allows passing to room-temperature operation (in the pulsed mode) and significant (by a factor of more than 1.7) variation in the output radiation frequency by simple variation in the pump intensity. A laser based on such a scheme can be a convenient and easily tunable source of infrared and terahertz radiation for both basic research and various applications.

Kukushkin, V. A., E-mail: vakuk@appl.sci-nnov.ru [Russian Academy of Sciences, Institute Applied Physics (Russian Federation)

2010-11-15T23:59:59.000Z

494

Terahertz radiation as a bunch diagnostic for laser-wakefield-accelerated electron bunches  

SciTech Connect (OSTI)

Experimental results are reported from two measurement techniques (semiconductor switching and electro-optic sampling) that allow temporal characterization of electron bunches produced by a laser-driven plasma-based accelerator. As femtosecond electron bunches exit the plasma-vacuum interface, coherent transition radiation (at THz frequencies) is emitted. Measuring the properties of this radiation allows characterization of the electron bunches. Theoretical work on the emission mechanism is presented, including a model that calculates the THz wave form from a given bunch profile. It is found that the spectrum of the THz pulse is coherent up to the 200 {micro}m thick crystal (ZnTe) detection limit of 4 THz, which corresponds to the production of sub-50 fs (rms) electron bunch structure. The measurements demonstrate both the shot-to-shot stability of bunch parameters that are critical to THz emission (such as total charge and bunch length), as well as femtosecond synchronization among bunch, THz pulse, and laser beam.

van Tilborg, Jeroen; Schroeder, Carl; Filip, Catalin; Toth, Csaba; Geddes, Cameron; Fubiani, Gwenael; Esarey, Eric; Leemans, Wim

2011-06-17T23:59:59.000Z

495

Ultrafast X-Ray Coherent Control  

SciTech Connect (OSTI)

This main purpose of this grant was to develop the nascent #12;eld of ultrafast x-ray science using accelerator-based sources, and originally developed from an idea that a laser could modulate the di#11;racting properties of a x-ray di#11;racting crystal on a fast enough time scale to switch out in time a shorter slice from the already short x-ray pulses from a synchrotron. The research was carried out primarily at the Advanced Photon Source (APS) sector 7 at Argonne National Laboratory and the Sub-Picosecond Pulse Source (SPPS) at SLAC; in anticipation of the Linac Coherent Light Source (LCLS) x-ray free electron laser that became operational in 2009 at SLAC (all National User Facilities operated by BES). The research centered on the generation, control and measurement of atomic-scale dynamics in atomic, molecular optical and condensed matter systems with temporal and spatial resolution . It helped develop the ultrafast physics, techniques and scienti#12;c case for using the unprecedented characteristics of the LCLS. The project has been very successful with results have been disseminated widely and in top journals, have been well cited in the #12;eld, and have laid the foundation for many experiments being performed on the LCLS, the world's #12;rst hard x-ray free electron laser.

Reis, David

2009-05-01T23:59:59.000Z

496

Femtosecond time-resolved spectroscopy of coherent oscillations in nanomaterials  

E-Print Network [OSTI]

FEMTOSECOND TIME-RESOLVED SPECTROSCOPY OF COHERENT OSCILLATIONS IN NANOMATERIALS A Dissertation by SERGUEI JEREBTSOV Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree... of DOCTOR OF PHILOSOPHY May 2007 Major Subject: Physics FEMTOSECOND TIME-RESOLVED SPECTROSCOPY OF COHERENT OSCILLATIONS IN NANOMATERIALS A Dissertation by SERGUEI JEREBTSOV Submitted to the Office of Graduate Studies of Texas A&M University in partial...

Jerebtsov, Serguei Nikolaevich

2009-05-15T23:59:59.000Z

497

Coherent flash of light emitted by a cold atomic cloud  

SciTech Connect (OSTI)

When a resonant laser sent on an optically thick cold atomic cloud is abruptly switched off, a coherent flash of light is emitted in the forward direction. This transient phenomenon is observed due to the highly resonant character of the atomic scatterers. We analyze quantitatively its temporal properties and show very good agreement with theoretical predictions. Based on complementary experiments, the phase of the coherent field is reconstructed without interferometric tools.

Chalony, M. [Institut Non Lineaire de Nice, Universite de Nice Sophia-Antipolis, CNRS, F-06560 Valbonne (France); Pierrat, R. [Institut Langevin, ESPCI ParisTech, CNRS UMR 7587, 10 rue Vauquelin, F-75005 Paris (France); Delande, D. [Laboratoire Kastler Brossel, UPMC-Paris 6, ENS, CNRS, 4 Place Jussieu, F-75005 Paris (France); Wilkowski, D. [Institut Non Lineaire de Nice, Universite de Nice Sophia-Antipolis, CNRS, F-06560 Valbonne (France); Centre for Quantum Technologies, National University of Singapore, 117543 Singapore (Singapore)

2011-07-15T23:59:59.000Z

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Wide-band coherent receiver development for enhanced surveillance  

SciTech Connect (OSTI)

Oak Ridge National Laboratory (ORNL) has been developing advanced coherent IR heterodyne receivers for plasma diagnostics in fusion reactors for over 20 years. Recent progress in wide band IR detectors and high speed electronics has significantly enhanced the measurement capabilities of coherent receivers. In addition, developments in new HgCdTe and quantum well IR photodetector (QWIP) focal plane arrays are providing the possibility of both active and passive coherent imaging. In this paper the authors discuss the implications of these new enabling technologies to the IR remote sensing community for enhanced surveillance. Coherent receivers, as opposed to direct or thermal detection, provide multiple dimensions of information about a scene or target in a single detector system. Combinations of range, velocity, temperature, and chemical species information are all available from a coherent heterodyne receiver.