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1

Laser Seeding Yields High-Power Coherent Terahertz Radiation  

NLE Websites -- All DOE Office Websites (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  

NLE Websites -- All DOE Office Websites (Extended Search)

Laser Seeding Yields High-Power Coherent Terahertz Radiation Print Researchers at Berkeley Lab have been exploring the ways coherent synchrotron radiation (CSR) is generated in...

3

Laser Seeding Yields High-Power Coherent Terahertz Radiation  

NLE Websites -- All DOE Office Websites (Extended Search)

Laser Seeding Yields High-Power Coherent Terahertz Radiation Print Laser Seeding Yields High-Power Coherent Terahertz Radiation Print Researchers at Berkeley Lab have been exploring the ways coherent synchrotron radiation (CSR) 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 Laser-Modulated Electron Beam"). In their most recent work, the researchers reported the first observation of seeding an instability of the electron beam by the laser, and they presented a physical model that shows how this occurs under the proper conditions. Such a mechanism makes it possible to control the instability onset and to exploit its gain for the generation of pulses of terahertz CSR of unprecedented power. Terahertz radiation with a wavelength from about 1 cm to about 100 microns between the microwave and the infrared would provide access to a large number of fundamental phenomena. To mention only some of them: excited electrons orbit, small molecules rotate, proteins vibrate, superconducting energy gaps resonate, and gaseous and solid-state plasmas oscillate at terahertz frequencies. But generating terahertz radiation is ordinarily a challenging task for any kind of source, including storage-ring-based synchrotron light sources. The new findings by the ALS group could represent a significant step toward satisfying the need for powerful terahertz sources.

4

Laser Seeding Yields High-Power Coherent Terahertz Radiation  

NLE Websites -- All DOE Office Websites (Extended Search)

Laser Seeding Yields High-Power Coherent Terahertz Radiation Print Laser Seeding Yields High-Power Coherent Terahertz Radiation Print Researchers at Berkeley Lab have been exploring the ways coherent synchrotron radiation (CSR) 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 Laser-Modulated Electron Beam"). In their most recent work, the researchers reported the first observation of seeding an instability of the electron beam by the laser, and they presented a physical model that shows how this occurs under the proper conditions. Such a mechanism makes it possible to control the instability onset and to exploit its gain for the generation of pulses of terahertz CSR of unprecedented power. Terahertz radiation with a wavelength from about 1 cm to about 100 microns between the microwave and the infrared would provide access to a large number of fundamental phenomena. To mention only some of them: excited electrons orbit, small molecules rotate, proteins vibrate, superconducting energy gaps resonate, and gaseous and solid-state plasmas oscillate at terahertz frequencies. But generating terahertz radiation is ordinarily a challenging task for any kind of source, including storage-ring-based synchrotron light sources. The new findings by the ALS group could represent a significant step toward satisfying the need for powerful terahertz sources.

5

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

6

High power terahertz generation using 1550?nm plasmonic photomixers  

SciTech Connect

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

7

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

SciTech Connect

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

8

Tunable terahertz coherent perfect absorption in a monolayer graphene  

E-Print Network (OSTI)

Coherent perfect absorber (CPA) was proposed as the time-reversed counterpart to laser: a resonator containing lossy medium instead of gain medium can absorb the coherent optical fields completely. Here, we exploit a monolayer graphene to realize the CPA in a non-resonant manner. It is found that quasi-CPA point exists in the terahertz regime for suspending monolayer graphene, and the CPA can be implemented with the assistant of proper phase modulation among two incident beams at the quasi-CPA frequencies. The graphene based CPA is found of broadband angular selectivity: CPA point splits into two frequency bands for the orthogonal $s$ and $p$ polarizations at oblique incidence, and the two bands cover a wide frequency range starting from zero frequency. Furthermore, the coherent absorption can be tuned substantially by varying the gate-controlled Fermi energy. The findings of CPA with non-resonant graphene sheet can be generalized for potential applications in terahertz/infrared detections and signal processi...

Fan, Yuancheng; Zhao, Qian; Wei, Zeyong; Li, Hongqiang

2014-01-01T23:59:59.000Z

9

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

SciTech Connect

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

10

High-power Er:YAG laser for coherent laser radar  

Science Journals Connector (OSTI)

We report the development of a high-power Er:YAG laser with high pulse energy for coherent lidar wind sensing. The 1.645 um Er:YAG laser produced a Q-switched pulse energy of 16 mJ...

Stoneman, Robert C; Malm, Andrew I R

11

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

SciTech Connect

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

12

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

13

High-power SRS lasers - coherent summators (the way it was)  

SciTech Connect

The history of the research works performed under the guidance of H.G. Basov and aimed at developing high-energy lasers - coherent summators (CSs) - based on stimulated Raman scattering (SRS) in liquid nitrogen and liquid oxygen is reported. The work was performed jointly by researchers of FIAN [the Laboratory of Quantum Radiophysics (LQRP)] and VNIIEF. Many problems were solved as a result of these studies. Liquid nitrogen and oxygen were found to be optimal active media for high-power SRS lasers with high energy per pulse. A method for purifying these cryogenic liquids from micro- and nanoimpurities was developed, which made it possible to eliminate nonlinear loss of pump radiation and converted radiation in the active medium and ensure effective operation of SRS lasers - coherent summators (SRSL CSs) with high output energy. Cryogenic cells providing high optical homogeneity of liquid nitrogen and oxygen were developed, which ensured low (at a level of 0.1 mrad) divergence of converted radiation with high energy density. Raster focusing systems providing optimal concentration of pump radiation in the active medium were designed. These studies resulted in the development of high-power highenergy SRSL CSs with a low beam divergence, based on liquid nitrogen ({lambda}{sub S} = 1.89 {mu}m) and liquid oxygen ({lambda}{sub S} = 1.65 {mu}m), with pumping by explosively pumped iodine lasers (EPILs) ({lambda}{sub p} = 1.315 {mu}m). The characteristics of the SRSL CSs developed were record for that time (the end of 1960s and the beginning of 1970s): energy up to 2.5 kJ per 10-{mu}s pulse, beam divergence {approx}10{sup -4} rad, and beam energy density of several hundreds of J cm{sup -2}. (special issue devoted to the 90th anniversary of n.g. basov)

Grasiuk, Arkadii Z; Zubarev, I G; Efimkov, V F; Smirnov, V G [P N Lebedev Physical Institute, Russian Academy of Sciences, Moscow (Russian Federation)

2012-12-31T23:59:59.000Z

14

Coherence and Linewidth Studies of a 4-nm High Power FEL  

E-Print Network (OSTI)

published in the Proceedings Coherence and Linewidth StudiesLBL-33285 HIFAN-570 Coherence and Linewidth Studies of a 4-No. DE-AC03-76SFOO098. Coherence and Linewidth Studies of a

Fawley, W.M.

2008-01-01T23:59:59.000Z

15

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

SciTech Connect

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

16

Nuclear Instruments and Methods in Physics Research A 507 (2003) 537540 Production of high power femtosecond terahertz radiation  

E-Print Network (OSTI)

Nuclear Instruments and Methods in Physics Research A 507 (2003) 537­540 Production of high power for Superconductor Photonics, Osaka University, 2-1 Yamadaoko, Suita, Osaka 565-0871, Japan e Physics Department semiconductors or electro-optic crystals by high peak power lasers. For example, this was done by using an un

17

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

SciTech Connect

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

18

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

SciTech Connect

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

19

Electrodynamics of high-temperature superconductors investigated with coherent terahertz pulse spectroscopy  

Science Journals Connector (OSTI)

Recent experimental investigations of the electrodynamic properties of high-temperature superconductors in the terahertz regime are reviewed. Transmission measurements were performed...

Brorson, S D; Buhleier, R; Trofimov, I E; White, J O; Ludwig, Ch; Balakirev, F F; Habermeier, H -U; Kuhl, Juergen

1996-01-01T23:59:59.000Z

20

PUBLISHED ONLINE: 15 MARCH 2009 | DOI: 10.1038/NPHYS1219 Observation of terahertz radiation coherently  

E-Print Network (OSTI)

coherently generated by acoustic waves Michael R. Armstrong1 *, Evan J. Reed1 , Ki-Yong Kim2 , James H

Loss, Daniel

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

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

22

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

23

High–power terahertz synchrotron sources  

Science Journals Connector (OSTI)

...figure 2a that the electric fields for wavelengths...Schematic of the distribution of electrons...of an electron energy of 10 MeV, and...longitudinal particle distribution within the bunch...bunches had an energy of 40 MeV, carried...We are now planning an upgrade to...Department of Energy under contract...

2004-01-01T23:59:59.000Z

24

Tailored Terahertz Pulses from a Laser-Modulated Electron Beam  

NLE Websites -- All DOE Office Websites (Extended Search)

at the ALS have demonstrated a new method to generate tunable, coherent, broadband terahertz radiation from a relativistic electron beam modulated by a femtosecond laser....

25

coherence  

Science Journals Connector (OSTI)

coherence [The property of wave trains being in phase. The coherence of adjacent seismic waves, along with an ... is the principal evidence for an event. Coherence is used qualitatively in picking ev...

2014-08-01T23:59:59.000Z

26

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

27

Tailored Terahertz Pulses from a Laser-Modulated Electron Beam  

NLE Websites -- All DOE Office Websites (Extended Search)

Tailored Terahertz Pulses from a Tailored Terahertz Pulses from a Laser-Modulated Electron Beam Tailored Terahertz Pulses from a Laser-Modulated Electron Beam Print Wednesday, 29 November 2006 00:00 Researchers at the ALS have demonstrated a new method to generate tunable, coherent, broadband terahertz radiation from a relativistic electron beam modulated by a femtosecond laser. Interaction of the ALS electron beam with a femtosecond laser pulse as they co-propagate through a wiggler modulates the electron energies within a short slice of the electron bunch with about the same duration as the laser pulse. This causes a dispersion of the electron trajectories, and the bunch develops a hole that emits short pulses of temporally and spatially coherent terahertz pulses synchronized to the laser. The technique allows tremendous flexibility in shaping the terahertz pulses by appropriate modulation of the laser pulse.

28

Coherent Synchrotron Radiation: Theory and Simulations.  

SciTech Connect

The physics of coherent synchrotron radiation (CSR) emitted by ultra-relativistic electron bunches, known since the last century, has become increasingly important with the development of high peak current free electron lasers and shorter bunch lengths in storage rings. Coherent radiation can be described as a low frequency part of the familiar synchrotron radiation in bending magnets. As this part is independent of the electron energy, the fields of different electrons of a short bunch can be in phase and the total power of the radiation will be quadratic with the number of electrons. Naturally the frequency spectrum of the longitudinal electron distribution in a bunch is of the same importance as the overall electron bunch length. The interest in the utilization of high power radiation from the terahertz and far infrared region in the field of chemical, physical and biological processes has led synchrotron radiation facilities to pay more attention to the production of coherent radiation. Several laboratories have proposed the construction of a facility wholly dedicated to terahertz production using the coherent radiation in bending magnets initiated by the longitudinal instabilities in the ring. Existing synchrotron radiation facilities also consider such a possibility among their future plans. There is a beautiful introduction to CSR in the 'ICFA Beam Dynamics Newsletter' N 35 (Editor C. Biscari). In this paper we recall the basic properties of CSR from the theory and what new effects, we can get from the precise simulations of the coherent radiation using numerical solutions of Maxwell's equations. In particular, transverse variation of the particle energy loss in a bunch, discovered in these simulations, explains the slice emittance growth in bending magnets of the bunch compressors and transverse de-coherence in undulators. CSR may play same the role as the effect of quantum fluctuations of synchrotron radiation in damping rings. It can limit the minimum achievable emittance in the synchrotron light sources for short bunches.

Novokhatski, Alexander; /SLAC

2012-03-29T23:59:59.000Z

29

High Power Cryogenic Targets  

SciTech Connect

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

30

Terahertz quantum cascade lasers  

Science Journals Connector (OSTI)

...Michael Pepper Terahertz quantum cascade lasers Jerome Faist 1 Lassaad Ajili...developments in terahertz quantum cascade lasers are reviewed. Structures...magnetic confinement| Terahertz quantum cascade lasers. | Recent developments in...

2004-01-01T23:59:59.000Z

31

Tailored Terahertz Pulses from a Laser-Modulated Electron Beam  

NLE Websites -- All DOE Office Websites (Extended Search)

Tailored Terahertz Pulses from a Laser-Modulated Electron Beam Print Tailored Terahertz Pulses from a Laser-Modulated Electron Beam Print Researchers at the ALS have demonstrated a new method to generate tunable, coherent, broadband terahertz radiation from a relativistic electron beam modulated by a femtosecond laser. Interaction of the ALS electron beam with a femtosecond laser pulse as they co-propagate through a wiggler modulates the electron energies within a short slice of the electron bunch with about the same duration as the laser pulse. This causes a dispersion of the electron trajectories, and the bunch develops a hole that emits short pulses of temporally and spatially coherent terahertz pulses synchronized to the laser. The technique allows tremendous flexibility in shaping the terahertz pulses by appropriate modulation of the laser pulse.

32

Tailored Terahertz Pulses from a Laser-Modulated Electron Beam  

NLE Websites -- All DOE Office Websites (Extended Search)

Tailored Terahertz Pulses from a Laser-Modulated Electron Beam Print Tailored Terahertz Pulses from a Laser-Modulated Electron Beam Print Researchers at the ALS have demonstrated a new method to generate tunable, coherent, broadband terahertz radiation from a relativistic electron beam modulated by a femtosecond laser. Interaction of the ALS electron beam with a femtosecond laser pulse as they co-propagate through a wiggler modulates the electron energies within a short slice of the electron bunch with about the same duration as the laser pulse. This causes a dispersion of the electron trajectories, and the bunch develops a hole that emits short pulses of temporally and spatially coherent terahertz pulses synchronized to the laser. The technique allows tremendous flexibility in shaping the terahertz pulses by appropriate modulation of the laser pulse.

33

Tailored Terahertz Pulses from a Laser-Modulated Electron Beam  

NLE Websites -- All DOE Office Websites (Extended Search)

Tailored Terahertz Pulses from a Laser-Modulated Electron Beam Print Tailored Terahertz Pulses from a Laser-Modulated Electron Beam Print Researchers at the ALS have demonstrated a new method to generate tunable, coherent, broadband terahertz radiation from a relativistic electron beam modulated by a femtosecond laser. Interaction of the ALS electron beam with a femtosecond laser pulse as they co-propagate through a wiggler modulates the electron energies within a short slice of the electron bunch with about the same duration as the laser pulse. This causes a dispersion of the electron trajectories, and the bunch develops a hole that emits short pulses of temporally and spatially coherent terahertz pulses synchronized to the laser. The technique allows tremendous flexibility in shaping the terahertz pulses by appropriate modulation of the laser pulse.

34

Surface-emitting distributed feedback terahertz quantum-cascade phase-locked laser arrays  

E-Print Network (OSTI)

A new approach to achieve high-power, symmetric beam-pattern, single-mode THz emission from metal-metal waveguide quantum-cascade laser is proposed and implemented. Several surface-emitting distributed feedback terahertz ...

Kao, Tsung-Yu

2009-01-01T23:59:59.000Z

35

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

36

Active Terahertz Metamaterial Devices  

NLE Websites -- All DOE Office Websites (Extended Search)

Active Terahertz Metamaterial Devices Active Terahertz Metamaterial Devices Active Terahertz Metamaterial Devices Metamaterial structures are taught which provide for the modulation of terahertz frequency signals. Available for thumbnail of Feynman Center (505) 665-9090 Email Active Terahertz Metamaterial Devices Metamaterial structures are taught which provide for the modulation of terahertz frequency signals. Each element within an array of metamaterial (MM) elements comprises multiple loops and at least one gap. The MM elements may comprise resonators with conductive loops and insulated gaps, or the inverse in which insulated loops are present with conductive gaps; each providing useful transmissive control properties. The metamaterial elements are fabricated on a semiconducting substrate configured with a

37

Terahertz Kerr effect  

E-Print Network (OSTI)

We have observed optical birefringence in liquids induced by single-cycle terahertz pulses with field strengths exceeding 100 kV/cm. The induced change in polarization is proportional to the square of the terahertz electric ...

Hoffmann, Matthias C.

38

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

SciTech Connect

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

39

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

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

40

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

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 Quantum Cascade Lasers  

Science Journals Connector (OSTI)

We provide an overview of terahertz quantum cascade lasers based on resonant-phonon depopulation and metal-metal waveguides, including two-phonon resonant-phonon depopulation...

Williams, Benjamin; Kumar, Sushil; Qin, Qi; Lee, Alan Wei Min; Hu, Qing; Reno, John L; Wasilewski, Z R; Liu, H C

42

High power gas laser amplifier  

DOE Patents (OSTI)

A high power output CO.sub.2 gas laser amplifier having a number of sections, each comprising a plurality of annular pumping chambers spaced around the circumference of a vacuum chamber containing a cold cathode, gridded electron gun. The electron beam from the electron gun ionizes the gas lasing medium in the sections. An input laser beam is split into a plurality of annular beams, each passing through the sections comprising one pumping chamber.

Leland, Wallace T. (Los Alamos, NM); Stratton, Thomas F. (Los Alamos, NM)

1981-01-01T23:59:59.000Z

43

Metamaterials for terahertz polarimetric devices  

SciTech Connect

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

44

Terahertz Quantum-Cascade Transmission-Line Metamaterials  

E-Print Network (OSTI)

Terahertz Transmission-Line Metamaterials . . . . . . .CRLH Transmission Lines . . . . . . . . . . . . . . . .Terahertz CRLH Transmission-Line Metamaterials . . . . . . .

Tavallaee, Amir Ali

2012-01-01T23:59:59.000Z

45

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

46

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

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

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...

47

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

48

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

49

Modulation instability in high power laser amplifiers  

E-Print Network (OSTI)

. Widmayer, R. K. White, S. T. Yang, and B. M. VanWonterghem, "National Ignition Facility laser performanceModulation instability in high power laser amplifiers Alexander M. Rubenchik,1,* Sergey K. Turitsyn in high-power laser systems. The so-called B-integral restriction is commonly used as the criteria for MI

Turitsyn, Sergei K.

50

Tunable terahertz radiation source  

SciTech Connect

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

51

The JLab high power ERL light source  

SciTech Connect

A new THz/IR/UV photon source at Jefferson Lab is the first of a new generation of light sources based on an Energy-Recovered, (superconducting) Linac (ERL). The machine has a 160 MeV electron beam and an average current of 10 mA in 75 MHz repetition rate hundred femtosecond bunches. These electron bunches pass through a magnetic chicane and therefore emit synchrotron radiation. For wavelengths longer than the electron bunch the electrons radiate coherently a broadband THz {approx} half cycle pulse whose average brightness is > 5 orders of magnitude higher than synchrotron IR sources. Previous measurements showed 20 W of average power extracted[1]. The new facility offers simultaneous synchrotron light from the visible through the FIR along with broadband THz production of 100 fs pulses with >200 W of average power. The FELs also provide record-breaking laser power [2]: up to 10 kW of average power in the IR from 1 to 14 microns in 400 fs pulses at up to 74.85 MHz repetition rates and soon will produce similar pulses of 300-1000 nm light at up to 3 kW of average power from the UV FEL. These ultrashort pulses are ideal for maximizing the interaction with material surfaces. The optical beams are Gaussian with nearly perfect beam quality. See www.jlab.org/FEL for details of the operating characteristics; a wide variety of pulse train configurations are feasible from 10 microseconds long at high repetition rates to continuous operation. The THz and IR system has been commissioned. The UV system is to follow in 2005. The light is transported to user laboratories for basic and applied research. Additional lasers synchronized to the FEL are also available. Past activities have included production of carbon nanotubes, studies of vibrational relaxation of interstitial hydrogen in silicon, pulsed laser deposition and ablation, nitriding of metals, and energy flow in proteins. This paper will present the status of the system and discuss some of the discoveries we have made concerning the physics performance, design optimization, and operational limitations of such a first generation high power ERL light source.

G.R. Neil; C. Behre; S.V. Benson; M. Bevins; G. Biallas; J. Boyce; J. Coleman; L.A. Dillon-Townes; D. Douglas; H.F. Dylla; R. Evans; A. Grippo; D. Gruber; J. Gubeli; D. Hardy; C. Hernandez-Garcia; K. Jordan; M.J. Kelley; L. Merminga; J. Mammosser; W. Moore; N. Nishimori; E. Pozdeyev; J. Preble; R. Rimmer; Michelle D. Shinn; T. Siggins; C. Tennant; R. Walker; G.P. Williams and S. Zhang

2005-03-19T23:59:59.000Z

52

High-Power Laser Beam Cladding  

Science Journals Connector (OSTI)

This paper reports major advances in the understanding, refinement and application of high-power laser beam cladding. The most important relationships between essential laser process variables and clad characteri...

G. J. Bruck

1987-02-01T23:59:59.000Z

53

An ultrafast carbon nanotube terahertz polarisation modulator  

SciTech Connect

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

54

Cavity enhanced terahertz modulation  

SciTech Connect

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

55

High Power Operation of the JLab IR FEL Driver Accelerator  

SciTech Connect

Operation of the JLab IR Upgrade FEL at CW powers in excess of 10 kW requires sustained production of high electron beam powers by the driver ERL. This in turn demands attention to numerous issues and effects, including: cathode lifetime; control of beamline and RF system vacuum during high current operation; longitudinal space charge; longitudinal and transverse matching of irregular/large volume phase space distributions; halo management; management of remnant dispersive effects; resistive wall, wake-field, and RF heating of beam vacuum chambers; the beam break up instability; the impact of coherent synchrotron radiation (both on beam quality and the performance of laser optics); magnetic component stability and reproducibility; and RF stability and reproducibility. We discuss our experience with these issues and describe the modus vivendi that has evolved during prolonged high current, high power beam and laser operation.

Kevin Beard; Stephen Benson; George Biallas; James Boyce; Donald Bullard; James Coleman; David Douglas; H. Dylla; Richard Evans; Pavel Evtushenko; Christopher Gould; Albert Grippo; Joseph Gubeli; David Hardy; Carlos Hernandez-Garcia; J. Hovater; Kevin Jordan; John Klopf; Rui Li; Steven Moore; George Neil; Benard Poelker; Thomas Powers; Joseph Preble; Robert Rimmer; Daniel Sexton; Michelle D. Shinn; Christopher Tennant; Richard Walker; Gwyn Williams; Shukui Zhang

2007-08-01T23:59:59.000Z

56

Plasma Switch for High-Power Active Pulse Compressor  

SciTech Connect

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

57

Modeling Combustion Control for High Power Diesel Mode Switching  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

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

58

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...

59

Abuse Testing of High Power Batteries | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Testing of High Power Batteries Abuse Testing of High Power Batteries 2009 DOE Hydrogen Program and Vehicle Technologies Program Annual Merit Review and Peer Evaluation Meeting,...

60

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...

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

Measuring Tiny Waves with High Power Particle Beams | Princeton...  

NLE Websites -- All DOE Office Websites (Extended Search)

Measuring Tiny Waves with High Power Particle Beams American Fusion News Category: U.S. Universities Link: Measuring Tiny Waves with High Power Particle Beams...

62

A Cooled Deformable Bimorph Mirror for a High Power Laser  

Science Journals Connector (OSTI)

Adaptive optics (AO) has been applied in various fields including astronomy, ophthalmology and high power laser systems. An adaptive optics system for a high power laser is not...

Lee, Jun-Ho; Lee, Young-Cheol; Kang, Eung-Cheol

2006-01-01T23:59:59.000Z

63

CHALLENGES FACING HIGH POWER PROTON ACCELERATORS  

SciTech Connect

This presentation will provide an overview of the challenges of high power proton accelerators such as SNS, J-PARC, etc., and what we have learned from recent experiences. Beam loss mechanisms and methods to mitigate beam loss will also be discussed.

Plum, Michael A [ORNL

2013-01-01T23:59:59.000Z

64

Profile Terahertz facility.pmd  

NLE Websites -- All DOE Office Websites (Extended Search)

Terahertz- and Millimeter-Wave Test Facility Terahertz- and Millimeter-Wave Test Facility B E N E F I T S Detect Terrorist-Related Contraband with Terahertz Technology * Spectral "fingerprints" uniquely identify materials * Can identify the factory where explosives and other chemicals were manufactured * Detects minute amounts of chemicals from a distance * Identifies materials in seconds Companies that develop or manufacture instruments to detect terrorist contraband can benefit by using a unique facility at the U.S. Department of Energy's Argonne National Laboratory. Called the Terahertz Test Facility, its sensitive, new instruments - developed at Argonne and available nowhere else in the world - can obtain spectral "fingerprints" that uniquely identify explosives, chemicals, and biological agents- and can even

65

Active terahertz metamaterial devices  

SciTech Connect

Metamaterial structures are taught which provide for the modulation of terahertz frequency signals. Each element within an array of metamaterial (MM) elements comprises multiple loops and at least one gap. The MM elements may comprise resonators with conductive loops and insulated gaps, or the inverse in which insulated loops are present with conductive gaps; each providing useful transmissive control properties. The metamaterial elements are fabricated on a semiconducting substrate configured with a means of enhancing or depleting electrons from near the gaps of the MM elements. An on to off transmissivity ratio of about 0.5 is achieved with this approach. Embodiments are described in which the MM elements incorporated within a Quantum Cascade Laser (QCL) to provide surface emitting (SE) properties.

Chen, Houtong (Los Alamos, NM); Padilla, Willie John (Newton, MA); Averitt, Richard Douglas (Newton, MA); O'Hara, John F. (Los Alamos, NM); Lee, Mark (Albuquerque, NM)

2010-11-02T23:59:59.000Z

66

Abuse Testing of High Power Batteries | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Abuse Testing of High Power Batteries Abuse Testing of High Power Batteries Presentation from the U.S. DOE Office of Vehicle Technologies "Mega" Merit Review 2008 on February 25,...

67

Abuse Testing of High Power Batteries | Department of Energy  

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

roth.pdf More Documents & Publications Abuse Tolerance Improvement Abuse Testing of High Power Batteries USABC Program Highlights...

68

Feedthrough terminal for high-power cell  

DOE Patents (OSTI)

A feedthrough terminal for a high power electrochemical storage cell providing low resistance coupling to the conductive elements therein while isolating the terminal electrode from the highly corrosive environment within the cell is disclosed. A large diameter, cylindrical copper electrode is enclosed in a stainless steel tube with a BN powder feedthrough seal maintained around the stainless steel tube by means of facing insulative bushings and an outer sleeve. One end of the copper conductor is silver-brazed directly to a flat, butterfly bus bar within the cell, with the adjacent end of the surrounding outer feedthrough sleeve welded to the bus bar. A threaded seal is fixedly positioned on a distal portion of the stainless steel tube immediately adjacent the distal insulative bushing so as to compress the feedthrough seal in tight fitting relation around the stainless steel tube in providing a rugged, leak-proof electrical feedthrough terminal for the power cell.

Kaun, T.D.

1982-05-28T23:59:59.000Z

69

partial coherence  

Science Journals Connector (OSTI)

In an electromagnetic wave, or waves, coherence such that the electromagnetic fields at two ... of correlation, i.e., have a coherence degree that is below 0.88 but...See also coherence

2001-01-01T23:59:59.000Z

70

Coherence - 2014  

NLE Websites -- All DOE Office Websites (Extended Search)

Coherence - 2014 International Workshop on Phase Retrieval and Coherent Scattering Argonne National Laboratory home program venue lodging exhibitors committees workshop Register...

71

High power linear pulsed beam annealer  

DOE Patents (OSTI)

A high power pulsed electron beam is produced in a system comprised of an electron gun having a heated cathode, control grid, focus ring, and a curved drift tube. The drift tube is maintained at a high positive voltage with respect to the cathode to accelerate electrons passing through the focus ring and to thereby eliminate space charge. A coil surrounding the curved drift tube provides a magnetic field which maintains the electron beam focused about the axis of the tube and imparts motion on electrons in a spiral path for shallow penetration of the electrons into a target. The curvature of the tube is selected so there is no line of sight between the cathode and a target holder positioned within a second drift tube spaced coaxially from the curved tube. The second tube and the target holder are maintained at a reference voltage that decelerates the electrons. A second coil surrounding the second drift tube maintains the electron beam focused about the axis of the second drift tube and compresses the electron beam to the area of the target. The target holder can be adjusted to position the target where the cross section of the beam matches the area of the target.

Strathman, Michael D. (Concord, CA); Sadana, Devendra K. (Berkeley, CA); True, Richard B. (Sunnyvale, CA)

1983-01-01T23:59:59.000Z

72

Terahertz detection and carbon nanotubes  

SciTech Connect

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

73

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

74

Terahertz spectroscopy for quantifying refined oil mixtures  

Science Journals Connector (OSTI)

In this paper, the absorption coefficient spectra of samples prepared as mixtures of gasoline and diesel in different proportions are obtained by terahertz time-domain spectroscopy. To...

Li, Yi-nan; Li, Jian; Zeng, Zhou-mo; Li, Jie; Tian, Zhen; Wang, Wei-kui

2012-01-01T23:59:59.000Z

75

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

76

High power fiber delivery for laser ignition applications  

Science Journals Connector (OSTI)

The present contribution provides a concise review of high power fiber delivery research for laser ignition applications. The fiber delivery requirements are discussed in terms of exit...

Yalin, Azer P

2013-01-01T23:59:59.000Z

77

Design and Control of High Power Density Motor Drive.  

E-Print Network (OSTI)

??This dissertation aims at developing techniques to achieve high power density in motor drives under the performance requirements for transportation system. Four main factors influencing… (more)

Jiang, Dong

2011-01-01T23:59:59.000Z

78

Advanced cathode material for high power applications.  

SciTech Connect

In our efforts to develop low cost high-power Li-ion batteries with excellent safety, as well as long cycle and calendar life, lithium manganese oxide spinel and layered lithium nickel cobalt manganese oxide cathode materials were investigated. Our studies with the graphite/LiPF{sub 6}/spinel cells indicated a very significant degradation of capacity with cycling at 55 C. This degradation was caused by the reduction of manganese ions on the graphite surface which resulted in a significant increase of the charge-transfer impedance at the anode/electrolyte interface. To improve the stability of the spinel, we investigated an alternative salt that would not generate HF acid that may attack the spinel. The alternative salt we selected for this work was lithium bisoxalatoborate, LiB(C{sub 2}O{sub 4}){sub 2} ('LiBoB'). In this case, the graphite/LiBoB/spinel Li-ion cells exhibited much improved cycle/calendar life at 55 C and better abuse tolerance, as well as excellent power. A second system based on LiNi{sub 1/3}Co{sub 1/3}Mn{sub 1/3}O{sub 2} layered material was also investigated and its performance was compared to commercial LiNi{sub 0.8}Co{sub 0.15}Al{sub 0.05}O{sub 2}. Cells based on LiNi{sub 1/3}Co{sub 1/3}Mn{sub 1/3}O{sub 2} showed lower power fade and better thermal safety than the LiNi{sub 0.8}Co{sub 0.15}Al{sub 0.05}O{sub 2}-based commercial cells under similar test conditions. Li-ion cells based on the material with excess lithium (Li{sub 1.1}Ni{sub 1/3}Co{sub 1/3}Mn{sub 1/3}O{sub 2}) exhibited excellent power performance that exceeded the FreedomCAR requirements.

Amine, K.; Belharouak, I.; Kang, S. H.; Liu, J.; Vissers, D.; Henriksen, G.; Chemical Engineering

2005-01-01T23:59:59.000Z

79

Quantifying Coherence  

Science Journals Connector (OSTI)

We introduce a rigorous framework for the quantification of coherence and identify intuitive and easily computable measures of coherence. We achieve this by adopting the viewpoint of coherence as a physical resource. By determining defining conditions for measures of coherence we identify classes of functionals that satisfy these conditions and other, at first glance natural quantities, that do not qualify as coherence measures. We conclude with an outline of the questions that remain to be answered to complete the theory of coherence as a resource.

T. Baumgratz; M. Cramer; M.?B. Plenio

2014-09-29T23:59:59.000Z

80

Quantifying Coherence  

E-Print Network (OSTI)

We introduce a rigorous framework for the quantification of coherence and identify intuitive and easily computable measures of coherence. We achieve this by adopting the viewpoint of coherence as a physical resource. By determining defining conditions for measures of coherence we identify classes of functionals that satisfy these conditions and other, at first glance natural quantities, that do not qualify as coherence measure. We conclude with an outline of the questions that remain to be answered to complete the theory of coherence as a resource.

T. Baumgratz; M. Cramer; M. B. Plenio

2013-11-01T23:59:59.000Z

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.


81

Terahertz generation by two cross focused laser beams in collisional plasmas  

SciTech Connect

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

82

JOSA COMMUNICATIONS Terahertz radiation from magnetoresistive  

E-Print Network (OSTI)

JOSA COMMUNICATIONS Terahertz radiation from magnetoresistive Pr0.7Ca0.3MnO3 thin films under University, 2-6 Yamadaoka, Suita, Osaka 565-0871, Japan Received April 11, 2005; revised July 17, 2005; accepted July 30, 2005 Terahertz (THz) radiation characteristics have been investigated for voltage

Tonouchi, Masayoshi

83

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

84

2nd High-Power Targetry Workshop MATERIAL IRRADIATION STUDIES  

E-Print Network (OSTI)

2nd High-Power Targetry Workshop MATERIAL IRRADIATION STUDIES FOR HIGH-INTENSITY PROTON BEAM thing: 4 MW on what spot size? #12;2nd High-Power Targetry Workshop Is there hope? Several "smart" materials or new composites may be able to meet some of the desired requirements: - new graphite grades

McDonald, Kirk

85

OPERATIONAL ASPECTS OF HIGH POWER ENERGY RECOVERY LINACS  

SciTech Connect

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

86

High-power LED Technology and Solid State Lighting  

Science Journals Connector (OSTI)

The rapid adoption of LEDs in general illumination is fueled by high-power phosphor-conversion and direct color blue and red LED technology. Over the last several years...

Goetz, Werner

87

Status and Prospects of Coherent Light Source Developments at UVSOR-II  

SciTech Connect

We are developing coherent light sources at the UVSOR-II electron storage ring. We have developed a resonator type free electron laser in the visible to the deep UV range, coherent harmonic generation source in VUV range and coherent synchrotron radiation source in the terahertz range. A new five year plan has been started from FY2008, where a new 4m straight section will be created by moving the beam injection point, a new optical klystron type undulator will be installed and dedicated beam-lines will be constructed. Great advances on the coherent light source developments at the new straight section are expected.

Adachi, Masahiro; Katoh, Masahiro; Zen, Heishun; Tanikawa, Takanori [UVSOR Facility, Institute for Molecular Science, National Institute of Natural Sciences, Okazaki, 444-8585 (Japan); School of Physical Sciences, Graduate University for Advanced Sciences, Okazaki, 444-8585 (Japan); Hosaka, Masahito; Takashima, Yoshifumi; Yamamoto, Naoto; Taira, Yoshitaka [Graduate School of Engineering, Nagoya University, Nagoya, 464-8603 (Japan)

2010-06-23T23:59:59.000Z

88

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

89

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

90

Graphene hyperlens for terahertz radiation  

Science Journals Connector (OSTI)

We propose a graphene hyperlens for the terahertz (THz) range. We employ and numerically examine a structured graphene-dielectric multilayered stack that is an analog of a metallic wire medium. As an example of the graphene hyperlens in action, we demonstrate an imaging of two point sources separated by a distance ?0/5. An advantage of such a hyperlens as compared to a metallic one is the tunability of its properties by changing the chemical potential of graphene. We also propose a method to retrieve the hyperbolic dispersion, check the effective medium approximation, and retrieve the effective permittivity tensor.

Andrei Andryieuski; Andrei V. Lavrinenko; Dmitry N. Chigrin

2012-09-27T23:59:59.000Z

91

Semiconductor superlattices as terahertz generators  

Science Journals Connector (OSTI)

Avoiding any truncation of the Hamiltonian for independent electrons in both ideal and imperfect superlattices subject to a uniform electric field, we show that dipole radiation in the terahertz range should be detectable for many members of the GaAs/AlxGa1-xAs system. The radiation can be attributed to periodic Bloch oscillations in the case of ideal superlattices, and to almost-periodic oscillations, with the dominant frequencies on the order of the Bloch frequency, in the case of imperfect superlattices.

Ann M. Bouchard and Marshall Luban

1993-03-15T23:59:59.000Z

92

Coherence holography  

Science Journals Connector (OSTI)

The principle of unconventional holography, called coherence holography, is proposed and experimentally demonstrated for the first time. An object recorded in a hologram is...

Takeda, Mitsuo; Wang, Wei; Duan, Zhihui; Miyamoto, Yoko

2005-01-01T23:59:59.000Z

93

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

94

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

95

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

96

Emission spectra of terahertz quantum cascade laser  

Science Journals Connector (OSTI)

We calculated energy levels, wave functions, and energies of radiative transitions in terahertz quantum cascade lasers based on GaAs/Al0.15Ga0.85As heterostructures. Current-voltage characteristics and current de...

A. V. Antonov; V. I. Gavrilenko; A. V. Ikonnikov…

2009-07-01T23:59:59.000Z

97

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

98

(1) (Handbook of Terahertz Technology) 2007127.3.6 LTEM  

E-Print Network (OSTI)

) 1 4 (1) (Handbook of Terahertz Technology) 200712§7.3.6 LTEM (2) (Handbook of Terahertz-ordered manganite" Rana, R; Pandey, P; Rana, DS; Mavani, KR; Kawayama, I; Murakami, H; Tonouchi, M, Physical Rev. B, LJ; Kang, L; Chen, J; Wu, PH; Tonouchi, M, New J. Physics 15 (2013) 055017 (5) "Terahertz nonlinear

Tonouchi, Masayoshi

99

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

SciTech Connect

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

100

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

SciTech Connect

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

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

High Power Electrodynamics (HPE): Accelerator Operations and Technology,  

NLE Websites -- All DOE Office Websites (Extended Search)

CONTACTS CONTACTS Group Leader Bruce Carlsten Deputy Group Leader Ellen Guenette Administrator Josephine (Jo) Torres High-Power Electrodynamics (HPE) The High-Power Electrodynamics (AOT-HPE) Group applies accelerator and beam technologies to national-security-directed energy missions. AOT-HPE has three programmatic thrusts: free-electron lasers (FELs), high-power microwaves (HPM), and compact radiography. To maintain a vigorous and robust technical base for addressing DOE and DoD needs, the group's project portfolio is balanced between exploratory research, infrastructure development, and programmatic deliverables for sponsors. Funding is roughly 25% from the Lab's Directed Research and Development Program, 65% from DoD, and 10% from DOE. Technology Focus Areas AOT-HPE is the Laboratory's main vehicle for applying accelerator-based technologies to directed-energy mission needs. The group recognizes that many directed-energy missions are enabled by compact high-brightness electron accelerators and mm-wave and THz technologies.

102

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

103

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

104

Coherence Current, Coherence Vortex, and the Conservation Law of Coherence  

Science Journals Connector (OSTI)

Introducing scalar and vector densities for a mutual coherence function, we present a new conservation law for optical coherence of scalar wave fields in the form of a continuity equation. This coherence conservation law provides new insights into topological phenomena for the complex coherence function. Some properties related to the newly introduced coherence vector density, such as a circulating coherence current associated with a coherence vortex, are investigated both theoretically and experimentally for the first time.

Wei Wang and Mitsuo Takeda

2006-06-08T23:59:59.000Z

105

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

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

EV) 3 CPI-LG Chem Mixed Mn-Oxide Cathodes (High Power) 4 JCS (Johnson Controls - Saft) Mixed Metal-Oxide Cathodes (High Power) 5 EnerDel Li-Titanate Anodes (High Power) PHEV...

106

Terahertz-based target typing.  

SciTech Connect

The purpose of this work was to create a THz component set and understanding to aid in the rapid analysis of transient events. This includes the development of fast, tunable, THz detectors, along with filter components for use with standard detectors and accompanying models to simulate detonation signatures. The signature effort was crucial in order to know the spectral range to target for detection. Our approach for frequency agile detection was to utilize plasmons in the channel of a specially designed field-effect transistor called the grating-gate detector. Grating-gate detectors exhibit narrow-linewidth, broad spectral tunability through application of a gate bias, and no angular dependence in their photoresponse. As such, if suitable sensitivity can be attained, they are viable candidates for Terahertz multi-spectral focal plane arrays.

Lyo, Sungkwun Kenneth; Wanke, Michael Clement; Reno, John Louis; Shaner, Eric Arthur; Grine, Albert D.; Barrick, Todd A.

2008-09-01T23:59:59.000Z

107

Catalytic Coherence  

Science Journals Connector (OSTI)

Because of 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 Åberg

2014-10-07T23:59:59.000Z

108

Coherence waves  

Science Journals Connector (OSTI)

In 1955 Wolf noticed that the mutual coherence function ? obeys two wave equations [Proc. R. Soc. London230, 246 (1955)]. The physical optics of this finding is thoroughly presented in...

Lohmann, Adolf W; Mendlovic, David; Shabtay, Gal

1999-01-01T23:59:59.000Z

109

Using a Balun Transformer Combiner for High Power Microwave Experiments  

SciTech Connect

A novel coaxial power combiner design has been duplicated that has distinct advantages over other combiner geometries that can handle high power. This design is being applied to combine four 3 kW power supplies to obtain a 10 kW, 5 MHz system for an ICRF antenna on HSX. In the past, Wilkinson type combiners have had limited application to high power systems because of the lack of non-inductive, high power, 100 Omega balance loads. With this new design, standard 50 Omega dummy loads can be used instead for the balance load. The cost is considerably lower than lumped element combiner designs which are dominated by capacitor costs. At such a relatively low frequency, a 3-dB quarter-wave coupled-line coupler becomes impractically long, and a conventional branch-line hybrid requires 35 Omega-line, which is commercially unavailable. The balun combiner uses less transmission line than a ring hybrid and has good bandwidth characteristics even away from its best line impedance. Theoretical calculations and modeling were performed for line impedances from 65 Omega to 75 Omega. Measurements from a low-power test device show excellent agreement with theory, and construction of the high power system is underway.

Kaufman, Michael C [ORNL; Pesavento, Philip V [ORNL

2011-01-01T23:59:59.000Z

110

High-power, high-intensity laser propagation and interactions  

SciTech Connect

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

111

Terahertz Light Source and User Area at FACET  

SciTech Connect

FACET at SLAC provides high charge, high peak current, low emittance electron beam that is bunched at THz wavelength scale during its normal operation. A THz light source based coherent transition radiation (CTR) from this beam would potentially be the brightest short-pulse THz source ever constructed. Efforts have been put into building this photon source together with a user area, to provide a platform to utilize this unique THz radiation for novel nonlinear and ultrafast phenomena researches and experiments. Being a long-time underutilized portion of the electromagnetic spectrum, terahertz (100 GHz {approx} 10 THz) spectral range is experiencing a renaissance in recent years, with broad interests from chemical and biological imaging, material science, telecommunication, semiconductor and superconductor research, etc. Nevertheless, the paucity of THz sources especially strong THz radiation hinders both its commercial applications and nonlinear processes research. FACET - Facilities for Accelerator science and Experimental Test beams at SLAC - provides 23 GeV electron beam with peak currents of {approx} 20 kA that can be focused down to 100 {mu}m{sup 2} transversely. Such an intense electron beam, when compressed to sub-picosecond longitudinal bunch length, coherently radiates high intensity EM fields well within THz frequency range that are orders of magnitude stronger than those available from laboratory tabletop THz sources, which will enable a wide variety of THz related research opportunities. Together with a description of the FACET beamline and electron beam parameters, this paper will report FACET THz radiation generation via coherent transition radiation and calculated photon yield and power spectrum. A user table is being set up along the THz radiation extraction sites, and equipped with various signal diagnostics including THz power detector, Michelson interferometer, sample stages, and sets of motorized optical components. This setup will also be presented. Potential THz research areas including studies of magnetism, ferroelectric switching dynamics, semiconductor devices and chemical reaction controls have already been proposed for the FACET THz area.

Wu, Z.; Li, S.Z.; Litos, M.; Fisher, A.D.; Hogan, M.J.; /SLAC

2011-11-08T23:59:59.000Z

112

Magneto-photonic phenomena at terahertz frequencies  

E-Print Network (OSTI)

Magneto-terahertz phenomena are the main focus of the thesis. This work started as supporting research for the science of an X-ray laser (SwissFEL). X-ray lasers have recently drawn great attention as an unprecedented tool for scientific research on the ultrafast scale..... To answer this fundamental question, we performed original numerical simulations using a coupled Landau- Lifshitz-Gilbert Maxwell model. ... Those requirements were the motivations for the experiments performed in the second part of the thesis. To shape the terahertz pulses, .... Regarding the field intensities, we followed two approaches. The first deals with field enhancement in nanoslits arrays. We designed a subwavelength structure characterized by simultaneous high field enhancement and high transmission at terahertz frequencies to suit nonlinear sources. The second approach depended on up-scaling the generation from laser-induced plasma by increasing the pump wavelengths. Numerical calculations have also brought to our attention the ...

Shalaby, Mostafa

2014-01-01T23:59:59.000Z

113

High Power Superconducting Continuous Wave Linacs for Protons and  

Office of Science (SC) Website

Power Superconducting Continuous Power Superconducting Continuous Wave Linacs for Protons and Heavy-Ions Nuclear Physics (NP) NP Home About Research Facilities Science Highlights Benefits of NP Spinoff Applications Spinoff Archives SBIR/STTR Applications of Nuclear Science and Technology Funding Opportunities Nuclear Science Advisory Committee (NSAC) News & Resources Contact Information Nuclear Physics U.S. Department of Energy SC-26/Germantown Building 1000 Independence Ave., SW Washington, DC 20585 P: (301) 903-3613 F: (301) 903-3833 E: sc.np@science.doe.gov More Information » Spinoff Archives High Power Superconducting Continuous Wave Linacs for Protons and Heavy-Ions Print Text Size: A A A RSS Feeds FeedbackShare Page Application/instrumentation: High Power Superconducting Continuous Wave Linacs for Protons and Heavy-Ions

114

Understanding High-Power Fiber-Optic Laser Beam Delivery  

NLE Websites -- All DOE Office Websites (Extended Search)

High-Power Fiber-Optic Laser Beam Delivery High-Power Fiber-Optic Laser Beam Delivery The submitted manuscript has been authored by a contractor of the U.S. Government under contract No. W- 31-109-ENG-38. Accordingly, the U.S. Government retains a nonexclusive, royalty-free license to publish or reproduce the published form of this contribution, or allow others to do so, for U.S. Government purposes. Boyd V. Hunter and Keng H. Leong Argonne National Laboratory Technology Development Division Laser Applications Laboratory 9700 South Cass Avenue, Building 207 Argonne, Illinois 60439 Carl B. Miller, James F. Golden, Robert D. Glesias and Patrick J. Laverty U. S. Laser Corporation 825 Windham Court North P. O. Box 609 Wyckoff, New Jersey 07481 March 25, 1996 Manuscript to be submitted to Journal of Laser Applications

115

High power l-band fast phase shifter  

SciTech Connect

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

116

Designing high power targets with computational fluid dynamics (CFD)  

SciTech Connect

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

117

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

118

High power test of a 57-MHz CW RFQ.  

SciTech Connect

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

119

13 - Terahertz (THz) quantum cascade lasers  

Science Journals Connector (OSTI)

Abstract: This chapter is dedicated to terahertz (THz) quantum cascade laser technology. After a brief introduction that contains a description of the current state of the art in terms of performance, the following important technological aspects are reviewed in more detail: waveguide and photonic structures, frequency and phase stabilisation, and active mode-locking.

S. Barbieri; S. Kumar

2013-01-01T23:59:59.000Z

120

Study of freshly excised brain tissues using terahertz imaging  

Science Journals Connector (OSTI)

We demonstrated that tumors in freshly excised whole brain tissue could be differentiated clearly from normal brain tissue using a reflection-type terahertz (THz) imaging system. THz...

Oh, Seung Jae; Kim, Sang-Hoon; Ji, Young Bin; Jeong, Kiyoung; Park, Yeonji; Yang, Jaemoon; Park, Dong Woo; Noh, Sam Kyu; Kang, Seok-Gu; Huh, Yong-Min; Son, Joo-Hiuk; Suh, Jin-Suck

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).
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

Low-Divergence Surface-Emitting Terahertz Quantum Cascade Lasers  

Science Journals Connector (OSTI)

We investigate surface-emission via a second-order grating in terahertz quantum cascade lasers. We optimize grating design and suppress facet reflectivity with absorbing waveguide...

Fan, Jonathan; Belkin, Mikhail; Capasso, Federico; Khanna, Suraj; Lachab, Mohammed; Davies, Giles; Linfield, Edmund

122

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

123

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

124

The Quest for Ultimate Broadband High Power Microwaves  

E-Print Network (OSTI)

Paper describes High Power Microwave research of combining GW peak power to achieve MV/m and GV/m radiated fields in 1 to 500 GHz band. To achieve such fields multiple independently triggered broadband GW sources, supplying power to multiple spatially distributed broadband radiators/antennas are used. Single TW array is used as an ultimate microwave weapon in 1 to 5 GHz range while multiple TW arrays provide GV/m radiating field at plasma frequencies in 300 GHz range leading to fusion power.

Podgorski, Andrew S

2014-01-01T23:59:59.000Z

125

High-power pulse modulator with ignitron discharger  

SciTech Connect

The high-power pulse modulator described here is used to produce spatial gaseous discharges and has an improved, controllable charging circuit, which permits a type ITR-4 ignitron discharger to be employed in a frequency mode as the basic commutator. The modulator is utilized in two modes: at a pulse repetition frequency of 50 Hz pulses are formed that have a duration of 25 usec and energies up to 3.5 kJ and at a frequency of 200 Hz, the pulses have a duration of -2 usec and energies up to 600 J. In all conditions the modulator operated stably with a wide range of load changes.

Anisimova, T.E.; Akkuratov, E.V.; Artemov, V.A.; Gromovenko, V.M.; Kalinin, V.P.; Nikonov, V.P.

1985-10-01T23:59:59.000Z

126

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

127

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

128

High-Power Directional Emission from Microlasers with Chaotic Resonators  

E-Print Network (OSTI)

High-power and highly directional semiconductor cylinder-lasers based on an optical resonator with deformed cross section are reported. In the favorable directions of the far-field, a power increase of up to three orders of magnitude over the conventional circularly symmetric lasers was obtained. A "bow-tie"-shaped resonance is responsible for the improved performance of the lasers in the higher range of deformations, in contrast to "whispering-gallery"-type modes of circular and weakly deformed lasers. This resonator design, although demonstrated here in midinfrared quantum-cascade lasers, should be applicable to any laser based on semiconductors or other high-refractive index materials.

Claire Gmachl; Federico Capasso; E. E. Narimanov; Jens U. Noeckel; A. Douglas Stone; Jerome Faist; Deborah L. Sivco; Alfred Y. Cho

1998-06-15T23:59:59.000Z

129

Diversion assumptions for high-powered research reactors  

SciTech Connect

This study deals with diversion assumptions for high-powered research reactors -- specifically, MTR fuel; pool- or tank-type research reactors with light-water moderator; and water, beryllium, or graphite reflectors, and which have a power level of 25 MW(t) or more. The objective is to provide assistance to the IAEA in documentation of criteria and inspection observables related to undeclared plutonium production in the reactors described above, including: criteria for undeclared plutonium production, necessary design information for implementation of these criteria, verification guidelines including neutron physics and heat transfer, and safeguards measures to facilitate the detection of undeclared plutonium production at large research reactors.

Binford, F.T.

1984-01-01T23:59:59.000Z

130

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

131

HIGH-POWER RF DISTRIBUTION SYSTEMFOR THE 8-PACK PROJECT  

SciTech Connect

The 8-Pack Project at SLAC is a prototype rf system whose goal is to demonstrate the high-power X-band technology developed in the NLC/GLC (Next/Global Linear Collider) program. In its first phase, it has reliably produced a 400 ns rf pulse of over 500 MW using a solidstate modulator, four 11.424 GHz klystrons and a dualmoded SLED-II pulse compressor. In Phase 2, the output power of the system has been delivered into the bunker of the NLCTA (Next Linear Collider Test Accelerator) and divided between several accelerator structures for beam acceleration. The authors describe here the design, cold-test measurements, and processing of this power distribution system. Due to the high power levels and the need for efficiency, overmoded waveguide and components are used. For power transport, the TE{sub 01} mode is used in 7.44 cm and 4.064 cm diameter circular waveguide. Only near the structures is standard WR90 rectangular waveguide employed. Components used to manipulate the rf power include transitional tapers, mode converters, overmoded bends, fractional directional couplers, and hybrids.

Nantista, C

2004-08-24T23:59:59.000Z

132

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

NLE Websites -- All DOE Office Websites (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...

133

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

E-Print Network (OSTI)

develop the high energy high power cathode materials for LIBNew Cathode Material for Batteries of High- Energy Density.High Energy High Power Li-ion Battery Cathode Materials A

Xu, Bo; Xu, Bo

2012-01-01T23:59:59.000Z

134

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

135

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

136

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

137

Application of High Powered Lasers to Perforated Completions  

NLE Websites -- All DOE Office Websites (Extended Search)

Congress on Applications of Laser & Electro-Optics Congress on Applications of Laser & Electro-Optics October 13 - 16, 2003, Jacksonville, Florida Application of High Powered Lasers to Perforated Completions Zhiyue Xu, Claude B. Reed and Keng H. Leong Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 R. A. Parker Parker Geoscience Consulting, LLC, 6346 Secrest Street, Arvada, CO 80403 R. M. Graves, Petroleum Engineering Department, Colorado School of Mines, Golden, CO 80401 ABSTRACT As part of the process of drilling an oil or gas well, a steel production casing is often inserted to the bottom of the well and sealed with cement against the productive formation. Openings must be made through the steel casing wall and cement and into the rock formation to allow formation fluid to enter the well. Conventionally, a perforator is

138

A low?frequency high?power magnetic drive transducer  

Science Journals Connector (OSTI)

Ralph Woollett's contributions to the art and science of sonartransducer design were as a researcher teacher author and reviewer. Of these roles perhaps the most important the one that became his legacy was that of teacher: All of his colleagues were in a sense his pupils. His careful and thorough approach to transducer design problems inspired us to try to meet his high standards and we still miss his insight advice encouragement and criticism. This talk will review Ralph's influence on underwater electroacoustics present some anecdotes about his life and work and examine the circumstances of his death. Finally it will show how Ralph's ideas and design philosophy have affected some of the author's present research specifically the design of a low?frequency high?power magnetic drive transducer having low distortion.

William J. Marshall

1990-01-01T23:59:59.000Z

139

An adaptive crystal bender for high power synchrotron radiation beams  

SciTech Connect

Perfect crystal monochromators cannot diffract x-rays efficiently, nor transmit the high source brightness available at synchrotron radiation facilities, unless surface strains within the beam footprint are maintained within a few arcseconds. Insertion devices at existing synchrotron sources already produce x-ray power density levels that can induce surface slope errors of several arcseconds on silicon monochromator crystals at room temperature, no matter how well the crystal is cooled. The power density levels that will be produced by insertion devices at the third-generation sources will be as much as a factor of 100 higher still. One method of restoring ideal x-ray diffraction behavior, while coping with high power levels, involves adaptive compensation of the induced thermal strain field. The design and performance, using the X25 hybrid wiggler beam line at the National Synchrotron Light Source (NSLS), of a silicon crystal bender constructed for this purpose are described.

Berman, L.E.; Hastings, J.B.

1992-01-01T23:59:59.000Z

140

An adaptive crystal bender for high power synchrotron radiation beams  

SciTech Connect

Perfect crystal monochromators cannot diffract x-rays efficiently, nor transmit the high source brightness available at synchrotron radiation facilities, unless surface strains within the beam footprint are maintained within a few arcseconds. Insertion devices at existing synchrotron sources already produce x-ray power density levels that can induce surface slope errors of several arcseconds on silicon monochromator crystals at room temperature, no matter how well the crystal is cooled. The power density levels that will be produced by insertion devices at the third-generation sources will be as much as a factor of 100 higher still. One method of restoring ideal x-ray diffraction behavior, while coping with high power levels, involves adaptive compensation of the induced thermal strain field. The design and performance, using the X25 hybrid wiggler beam line at the National Synchrotron Light Source (NSLS), of a silicon crystal bender constructed for this purpose are described.

Berman, L.E.; Hastings, J.B.

1992-10-01T23:59:59.000Z

Note: This page contains sample records for the topic "high-power coherent terahertz" from the National Library of EnergyBeta (NLEBeta).
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141

High power density AEM combustion for TPV applications  

Science Journals Connector (OSTI)

Various emitter designs and compositions are investigated to improve the performance and reduce the cost of thermophotovoltaic (TPV) devices. In order to maximize the overall system efficiency of combustion-powered TPV devices it is desirable to design an emitter system that will provide a high and uniform volumetric heat release producing a high intensity and uniform in-band photons flux thus enabling reduced size and weight of TPV generators. Quantum Group Inc. (QGI) has developed a high power density radiant burner/emitter technology which we have called Advanced Emissive Matrix (AEM). The AEM system is applicable to broad-band and narrow-band TPV approaches. Several AEM combustors-both broad-band and narrow-band-have been built tested and have consistently demonstrated extremely high power density (up to 30 W/cm3). Radiant emissions greater than 27 W/cm2 were measured from an AEM combustor fired with natural gas at 15% excess air. This level of radiant heat flux enables the utilization of concentrator-type PV cells which is a method of reducing cost size and weight of TPV devices. Additionally it was found that the AEM structure could be engineered to provide a desired radiant emission profile. The influence of the primary combustion parameters on emitter performance will also be presented. Therefore integration of the narrow-band emitter materials into an AEM combustor results in the delivery of high intensity selective and uniform photons to the PV cell face that improves TPV device performance.

Aleksandr S. Kushch; Steven M. Skinner

1999-01-01T23:59:59.000Z

142

Classical versus quantum coherence  

Science Journals Connector (OSTI)

...M. Stoneham Classical versus quantum coherence P. T. Greenland Department of Physics...nanostructures| Classical versus quantum coherence. | Quantum dots are structures engineered...2002.1134 Classical versus quantum coherence By P. T. Greenland Department of Physics...

2003-01-01T23:59:59.000Z

143

Unexpected coherence and conservation  

Science Journals Connector (OSTI)

...December 2001 research-article Unexpected coherence and conservation Bernard Cazelles 1...out-of-phase synchrony| Unexpected coherence and conservation. | The effects of migration...Behavior Stochastic Processes Unexpected coherence and conservation Bernard Cazelles1...

2001-01-01T23:59:59.000Z

144

The Coherence Premium:.  

E-Print Network (OSTI)

??Evidence was found for the partial explanation of firm succes from a new point of view: coherence. A positive relationship was found between coherence, a… (more)

Van Braam Houckgeest, A.Q.

2012-01-01T23:59:59.000Z

145

Sense of coherence.  

E-Print Network (OSTI)

?? The aim of the study was to investigate the sense of coherence among students in Zambia. Sense of coherence was assessed with the questionnaire… (more)

Lennqvist, Susanne

2009-01-01T23:59:59.000Z

146

Understanding Causal Coherence Relations.  

E-Print Network (OSTI)

??The research reported in this dissertation focuses on the cognitive processes and representations involved in understanding causal coherence relations in text. Coherence relations are the… (more)

Mulder, G.

2008-01-01T23:59:59.000Z

147

Coherence in Oxygenic Photosynthesis  

Science Journals Connector (OSTI)

We report coherent dynamics in the photosystem II reaction center observed by two dimensional electronic spectroscopy. We discuss the physical nature of the coherences and their...

Fuller, Franklin D; Pan, Jie; Gelzinis, Andrius; Butkus, Vytautas; Senlik, Seckin; Wilcox, Daniel E; Valkunas, Leonas; Abramavicius, Darius; Ogilvie, Jennifer P

148

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

SciTech Connect

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

149

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

150

Cutting and drilling studies using high power visible lasers  

SciTech Connect

High power and radiance laser technologies developed at Lawrence Livermore National Laboratory such as copper-vapor and dye lasers show great promise for material processing tasks. Evaluation of models suggests significant increases in welding, cutting, and drilling capabilities, as well as applications in emerging technologies such as micromachining, surface treatment, and stereolithography. Copper lasers currently operate at 1.8 kW output at approximately three times the diffraction limit and achieve mean time between failures of more than 1,000 hours. Dye lasers have near diffraction limited beam quality at greater than 1.0 kW. Results from cutting and drilling studies in titanium and stainless steel alloys show that cuts and holes with extremely fine features can be made with dye and copper-vapor lasers. High radiance beams produce low distortion and small heat-affected zones. The authors have accomplished very high aspect ratios (> 60:1) and features with micron scale (5-50 {mu}m) sizes. The paper gives a description of the equipment; discusses cutting theory; and gives experimental results of cutting and drilling studies on Ti-6Al-4V and 304 stainless steel.

Kautz, D.D.; Dragon, E.P.; Werve, M.E.; Hargrove, R.S.; Warner, B.E.

1993-05-27T23:59:59.000Z

151

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

SciTech Connect

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

152

High power continuous-wave titanium:sapphire laser  

DOE Patents (OSTI)

A high-power continuous-wave laser resonator is provided, wherein first, second, third, fourth, fifth and sixth mirrors form a double-Z optical cavity. A first Ti:sapphire rod is disposed between the second and third mirrors and at the mid-point of the length of the optical cavity, and a second Ti:sapphire rod is disposed between the fourth and fifth mirrors at a quarter-length point in the optical cavity. Each Ti:sapphire rod is pumped by two counter-propagating pump beams from a pair of argon-ion lasers. For narrow band operation, a 3-plate birefringent filter and an etalon are disposed in the optical cavity so that the spectral output of the laser consists of 5 adjacent cavity modes. For increased power, seventy and eighth mirrors are disposed between the first and second mirrors to form a triple-Z optical cavity. A third Ti:sapphire rod is disposed between the seventh and eighth mirrors at the other quarter-length point in the optical cavity, and is pumped by two counter-propagating pump beams from a third pair of argon-ion lasers. 5 figures.

Erbert, G.V.; Bass, I.L.; Hackel, R.P.; Jenkins, S.L.; Kanz, V.K.; Paisner, J.A.

1993-09-21T23:59:59.000Z

153

High power KrF laser development at Los Alamos  

SciTech Connect

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

154

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

155

Plasma potential mapping of high power impulse magnetron sputtering discharges  

SciTech Connect

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

156

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

157

Safety approaches for high power modular laser operation  

SciTech Connect

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

158

Granular Structure Determined by Terahertz Scattering  

E-Print Network (OSTI)

Light-scattering in the terahertz region is demonstrated for granular matter. A quantum-cascade laser is used in a benchtop setup to determine the angle-dependent scattering of spherical grains as well as coffee powder and sugar grains. For the interpretation of the form factors for the scattering from single particles one has to go beyond the usual Rayleigh-Gans-Debye theory and apply calculations within Mie theory. In addition to single scattering also collective correlations can be identified and extracted as a static structure factor.

Philip Born; Nick Rothbart; Matthias Sperl; Heinz-Wilhelm Hübers

2013-12-23T23:59:59.000Z

159

HIGH-POWER MILLIMETREWAVE TRANSMISSION SYSTEMS AND COMPONENTS FOR ELECTRON CYCLOTRON HEATING OF FUSION PLASMAS  

Science Journals Connector (OSTI)

At the Institute for Plasma Research at the University of Stuttgart, high-power millimetre wave transmission systems for electron cyclotron heating (ECRH) and current drive (ECCD)...

W. Kasparek; G. Dammertz; V. Erckmann…

2005-01-01T23:59:59.000Z

160

Terahertz imaging system performance model for concealed-weapon identification  

Science Journals Connector (OSTI)

The U.S. Army Night Vision and Electronic Sensors Directorate (NVESD) and the U.S. Army Research Laboratory have developed a terahertz (THz) -band imaging system performance model...

Murrill, Steven R; Jacobs, Eddie L; Moyer, Steven K; Halford, Carl E; Griffin, Steven T; De Lucia, Frank C; Petkie, Douglas T; Franck, Charmaine C

2008-01-01T23:59:59.000Z

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.


161

Bilayer-fish-scale ultrabroad terahertz bandpass filter  

Science Journals Connector (OSTI)

A bilayer fish-scale metamaterial is experimentally demonstrated to function as a broad bandpass filter in the terahertz regime. The measured 3 dB-bandwidth for normal incidence is...

Zhang, Xueqian; Gu, Jianqiang; Cao, Wei; Han, Jiaguang; Lakhtakia, Akhlesh; Zhang, Weili

2012-01-01T23:59:59.000Z

162

Development of tunable terahertz quantum cascade wire lasers  

E-Print Network (OSTI)

For a long time, terahertz (THz) radiation has been of great interest to scientific community because of its spectroscopic and imaging applications based on its unique properties, such as the capabilities to penetrate many ...

Qin, Qi, Ph. D. Massachusetts Institute of Technology

2012-01-01T23:59:59.000Z

163

A Source for Ultrafast Continuum Infrared and Terahertz Radiation  

E-Print Network (OSTI)

A compact and stable method for generating high-intensity linearly polarized continuum mid-IR and terahertz light using ultrafast femtosecond (fs) laser pulses is demonstrated. Continuous light generation from <400cm?1 ...

Petersen, Poul B.

164

Theoretical and computational design of terahertz frequency quantum cascade lasers  

Science Journals Connector (OSTI)

Modeling of terahertz frequency quantum cascade lasers has become increasingly complex theoretically resulting in burdensome computational requirements. While more comprehensive treatment permits further insight and increased accuracy the modeling of ...

Adam T. Cooney / A.M. Sarangan

2009-01-01T23:59:59.000Z

165

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

166

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

167

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

168

Terahertz quantum cascade lasers based on resonant phonon scattering for depopulation  

Science Journals Connector (OSTI)

...Michael Pepper Terahertz quantum cascade lasers based on resonant phonon...development of terahertz (THz) quantum cascade lasers (QCLs), in which the depopulation...intersubband|quantum wells|quantum cascade lasers|longitudinal optical...

2004-01-01T23:59:59.000Z

169

Graphene-Based Plasmonic Platform for Reconfigurable Terahertz Nanodevices  

Science Journals Connector (OSTI)

Graphene-Based Plasmonic Platform for Reconfigurable Terahertz Nanodevices ... We propose here a new platform to realize a plethora of graphene-based plasmonic nanodevices for frequency-agile terahertz (THz) frontend circuits. ... We demonstrate that a class of hybrid electronic-plasmonic nanodevices combining active graphene field-effect transistors (GFET) and graphene plasmonic waveguides (GPWG) supporting tightly confined propagation of THz signals, with tailored phase velocity and characteristic impedance controlled by the gate and drain voltages of GFET. ...

Pai-Yen Chen; Haiyu Huang; Deji Akinwande; Andrea Alù

2014-07-07T23:59:59.000Z

170

The Coherence of Stoic Ontology  

E-Print Network (OSTI)

The Coherence of Stoic Ontology by Vanessa de Harven ALong Spring 2012 Abstract The Coherence of Stoic Ontology byof charity that seeks coherence in the Stoics and something

de Harven, Vanessa

2012-01-01T23:59:59.000Z

171

Characterization of terahertz emission from a dc-biased filament in air  

SciTech Connect

We demonstrate that the terahertz emission from a dc-biased filament can be regarded as a sum of an elliptically polarized terahertz source (generated by a filament without external electric field) and a linearly polarized terahertz source induced by the external electric field applied to the filament. The peak frequency and linewidth of the linearly polarized terahertz source are related to the average plasma density of the filament.

Chen Yanping; Wang Tiejun; Marceau, Claude; Chin, See Leang [Centre d'Optique, Photonique et Laser (COPL), and Departement de Physique, de genie physique et d'optique, Universite Laval, Quebec, Quebec G1V 0A6 (Canada); Theberge, Francis; Chateauneuf, Marc; Dubois, Jacques [Defence Research and Development Canada-Valcartier, 2459 Pie-XI Blvd. North, Quebec, Quebec G3J 1X5 (Canada); Kosareva, Olga [International Laser Center, Physics Department, M.V. Lomonosov Moscow State University, Moscow 119992 (Russian Federation)

2009-09-07T23:59:59.000Z

172

Cryogenic temperatures as a path toward high-Q terahertz metamaterials Ranjan Singh,1,2  

E-Print Network (OSTI)

Cryogenic temperatures as a path toward high-Q terahertz metamaterials Ranjan Singh,1,2 Zhen Tian,1 terahertz time-domain spectroscopy. The operation of metamaterials at cryogenic temperatures is anticipated we investigate the behavior of terahertz planar MM at cryogenic temperatures. It is shown that thin

Oklahoma State University

173

Self-normalizing phase measurement in multimode terahertz spectroscopy based on photomixing of three lasers  

E-Print Network (OSTI)

Photomixing of two near-infrared lasers is well established for continuous-wave terahertz spectroscopy. Photomixing of three lasers allows us to measure at three terahertz frequencies simultaneously. Similar to Fourier spectroscopy, the spectral information is contained in an nterferogram, which is equivalent to the waveform in time-domain spectroscopy. We use one fixed terahertz frequency \

Thirunavukkuarasu, K; Roggenbuck, A; Vidal, E; Schmitz, H; Hemberger, J; Grüninger, M

2014-01-01T23:59:59.000Z

174

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

175

Generation of 1.5-kW, 1-THz Coherent Radiation from a Gyrotron with a Pulsed Magnetic Field  

Science Journals Connector (OSTI)

To cover a so-called terahertz gap in available sources of coherent electromagnetic radiation, the gyrotron with a pulsed solenoid producing up to a 40 T magnetic field has been designed, manufactured, and tested. At a 38.5 T magnetic field, the gyrotron generated coherent radiation at 1.022 THz frequency in 50???sec pulses. The microwave power and energy per pulse were about 1.5 kW and 75 mJ, respectively. Details of the gyrotron design, manufacturing, operation and measurements of output radiation are given.

M. Yu. Glyavin; A. G. Luchinin; G. Yu. Golubiatnikov

2008-01-11T23:59:59.000Z

176

LLCC-PWM Inverter for Driving High-Power Piezoelectric Actuators  

E-Print Network (OSTI)

LLCC-PWM Inverter for Driving High-Power Piezoelectric Actuators Rongyuan Li, Norbert Fröhleke LLCC-PWM inverter is presented for driving ultrasonic high power piezoelectric actuators. The proposed system of a pulse- width modulated inverter and LLCC-type filter is designed in a way to reduce the total

Paderborn, Universität

177

Flow and heat transfer in porous micro heat sink for thermal management of high power LEDs  

Science Journals Connector (OSTI)

A novel porous micro heat sink system is presented for thermal management of high power LEDs, which has high heat transport capability. The operational principle and heat transfer characteristics of porous micro heat sink are analyzed. Numerical model ... Keywords: Heat dissipation, High heat flux, High power LEDs, Porous media, Porous micro heat sink

Z. M. Wan; J. Liu; K. L. Su; X. H. Hu; S. S. M

2011-05-01T23:59:59.000Z

178

Modeling of dimmable High Power LED illumination distribution using ANFIS on the isolated area  

Science Journals Connector (OSTI)

High power light emitting diodes (HP-LEDs) are more suitable for energy saving applications and have becoming replacing traditional fluorescent and incandescent bulbs for its energy efficient. Therefore, HP-LED lighting has been regarded in the next-generation ... Keywords: ANFIS, High Power LED, Illumination distribution

?smail Kiyak; Vedat Topuz; Bülent Oral

2011-09-01T23:59:59.000Z

179

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

180

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

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

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

182

A LOW-DISTORTION CLASS-AB AUDIO AMPLIFIER WITH HIGH POWER EFFICIENCY  

E-Print Network (OSTI)

A LOW-DISTORTION CLASS-AB AUDIO AMPLIFIER WITH HIGH POWER EFFICIENCY BY CHAITANYA MOHAN, B of Sciences, Engineering Specialization in: Electrical Engineering New Mexico State University Las Cruces, New Mexico March 2011 #12;"A Low-Distortion Class-AB Audio Amplifier with High Power Efficiency," a the- sis

Furth, Paul

183

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

SciTech Connect

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

184

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

185

Deductive coherence and norm adoption  

Science Journals Connector (OSTI)

......Issue: Normative Multiagent Systems Deductive coherence and norm adoption Sindhu Joseph Artificial Intelligence...contribution to the formalisation of Thagards coherence theory. The term coherence is defined as the quality or the state of cohering......

Sindhu Joseph; Carles Sierra; Marco Schorlemmer; Pilar Dellunde

2010-02-01T23:59:59.000Z

186

Coherence versus interferometric resolution  

Science Journals Connector (OSTI)

We examine the relation between second-order coherence and resolution in the interferometric detection of phase shifts. While for classical thermal light resolution and second-order coherence are synonymous, we show that for quantum light beams reaching optimum precision second-order coherence and resolution become antithetical.

Alfredo Luis

2010-06-30T23:59:59.000Z

187

Coherence versus interferometric resolution  

SciTech Connect

We examine the relation between second-order coherence and resolution in the interferometric detection of phase shifts. While for classical thermal light resolution and second-order coherence are synonymous, we show that for quantum light beams reaching optimum precision second-order coherence and resolution become antithetical.

Luis, Alfredo [Departamento de Optica, Facultad de Ciencias Fisicas, Universidad Complutense, 28040 Madrid (Spain)

2010-06-15T23:59:59.000Z

188

Terahertz graphene lasers: Injection versus optical pumping  

SciTech Connect

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

189

Terahertz-driven linear electron acceleration  

E-Print Network (OSTI)

The cost, size and availability of electron accelerators is dominated by the achievable accelerating gradient. Conventional high-brightness radio-frequency (RF) accelerating structures operate with 30-50 MeV/m gradients. Electron accelerators driven with optical or infrared sources have demonstrated accelerating gradients orders of magnitude above that achievable with conventional RF structures. However, laser-driven electron accelerators require intense sources and suffer from low bunch charge, sub-micron tolerances and sub-femtosecond timing requirements due to the short wavelength of operation. Here, we demonstrate the first linear acceleration of electrons with keV energy gain using optically-generated terahertz (THz) pulses. THz-driven accelerating structures enable high-gradient electron accelerators with simple accelerating structures, high repetition rates and significant charge per bunch. Increasing the operational frequency of accelerators into the THz band allows for greatly increased accelerating ...

Nanni, Emilio Alessandro; Ravi, Koustuban; Fallahi, Arya; Moriena, Gustavo; Miller, R J Dwayne; Kärtner, Franz X

2014-01-01T23:59:59.000Z

190

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

Energy.gov (U.S. Department of Energy (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...

191

Digital Photonic Production: High Power ultrashort Lasers, Laser Additive Manufacturing and Laser Micro/ Nano Fabrication  

Science Journals Connector (OSTI)

The high power optical technologies enter a new era: The age of DIGITAL PHOTONIC PRODUCTION. Very recently new lasers in new time- and wavelength domains with high average powers have...

Poprawe, Reinhart; Gillner, Arnold; Hoffmann, Dieter; Kelbassa, Ingomar; Loosen, Peter; Wissenbach, Konrad

192

Cryogenic, high power, near diffraction limited, Yb:YAG slab laser  

Science Journals Connector (OSTI)

A cryogenic slab laser that is suitable for scaling to high power, while taking full advantage of the improved thermo-optical and thermo-mechanical properties of Yb:YAG at cryogenic...

Ganija, Miftar; Ottaway, David; Veitch, Peter; Munch, Jesper

2013-01-01T23:59:59.000Z

193

Statistical analysis and optimization of processing parameters in high-power direct diode laser cladding  

Science Journals Connector (OSTI)

High-power direct diode laser (HPDDL) offers a wide laser beam with a top-hat intensity distribution, ... making it an ideal tool for large-area cladding. In this study, a systemic study on the HPDDL cladding pro...

Shuang Liu; Radovan Kovacevic

2014-09-01T23:59:59.000Z

194

High Energy Density Sate, Material and Device with High Power Lasers  

Science Journals Connector (OSTI)

High energy density states with photon pressures of more than Tera bar and thermal pressure of more than Mega bar, is now available with high power lasers. Here I present creation of...

Kodama, R

195

3-Dimensional thermal analysis and active cooling of short-length high-power fiber lasers  

Science Journals Connector (OSTI)

A fully 3-dimensional finite element model has been developed that simulates the internal temperature distribution of short-length high-power fiber lasers. We have validated the...

Li, L; Li, H; Qiu, T; Temyanko, V L; Morrell, M M; Schülzgen, A; Mafi, A; Moloney, J V; Peyghambarian, N

2005-01-01T23:59:59.000Z

196

Cryogenic Intracavity Laser Cooling Using High Power Vertical External Cavity Surface Emitting Lasers (VECSELs)  

Science Journals Connector (OSTI)

A Yb:YLF crystal is laser cooled to 150 K from room temperature in an intracavity geometry using a high power InGaAs/GaAs MQW VECSEL operating at 1020 nm with <0.5 nm linewidth.

Ghasemkhani, Mohammadreza; Albrecht, Alexander R; Melgaard, Seth; Seletskiy, Denis V; Cederberg, Jeffrey G; Sheik-Bahae, Mansoor

197

Sapphire-conductive end-cooling of high power cryogenic Yb:YAG laser  

Science Journals Connector (OSTI)

We have demonstrated a high-power laser oscillator with end-cooling using a sapphire-sandwiched Yb:YAG disk at near liquid nitrogen temperature. An output power of 74 W with...

Tokita, Shigeki; Kawanaka, Junji; Izawa, Yasukazu; Fujita, Masayuki; Kawashima, Toshiyuki

198

Heating by Optical Absorption and Cooling of High Power Laser Mirrors  

Science Journals Connector (OSTI)

In high power laser system, laser mirror is the core and the most sensitive optical component, which influences the increase of laser power and the quality of laser. Absorption of light at mirrors causes wavef...

Ci-Ming Zhou; Zu-Hai Cheng; Yu-Feng Peng

2003-12-01T23:59:59.000Z

199

Sapphire-Conductive End-Cooling of High Power Cryogenic Yb:YAG Laser  

Science Journals Connector (OSTI)

We have demonstrated a high-power laser oscillator with end-cooling using a sapphire-sandwiched Yb:YAG disk at liquid nitrogen temperature. An output power of 74 W with...

Tokita, Shigeki; Fujita, Masayuki; Kawanaka, Junji; Kawashima, Toshiyuki; Izawa, Yasukazu

200

Ignition studies in support of the European High Power Laser Energy Research Facility project  

Science Journals Connector (OSTI)

The European High Power Laser Energy Research Facility (HiPER) project is ... of the fusion target mixing prior to thermonuclear ignition have been investigated using the 1D Lagrangian...Z ion species may inhibit...

J. Pasley

2010-11-01T23:59:59.000Z

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.


201

Argonne National Laboratory Terahertz- and Millimeter-Wave Test Facility  

NLE Websites -- All DOE Office Websites (Extended Search)

PROFILE: PROFILE: Argonne Homeland Security Technologies APPLICATIONS A R G O N N E N A T I O N A L L A B O R A T O R Y Terahertz- and Millimeter-Wave Test Facility B E N E F I T S Detect Terrorist-Related Contraband with Terahertz Technology * Spectral "fingerprints" uniquely identify materials * Can identify the factory where explosives and other chemicals were manufactured * Detects minute amounts of chemicals from a distance * Identifies materials in seconds Companies that develop or manufacture instruments to detect terrorist contraband can benefit by using a unique facility at the U.S. Department of Energy's Argonne National Laboratory. Called the Terahertz Test Facility, its sensitive, new instruments - developed at Argonne and available nowhere else in the world - can obtain spectral "fingerprints" that uniquely

202

A 25 KV/10A PULSER FOR DRIVING A HIGH-POWER PIERCE ELECTRON GUN  

E-Print Network (OSTI)

A 25 KV/10A PULSER FOR DRIVING A HIGH-POWER PIERCE ELECTRON GUN J. J. Barroso, J. O. Rossi, H-tube pulser to drive a high-power electron gun. The tube includes a 2.0µF/100kV capacitor bank whose discharge is controlled by a tetrode tube connected to the gun cathode. Typical measured operating parameters are 3

203

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

204

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

205

Coherence of neutron fields  

Science Journals Connector (OSTI)

Glauber's definition of quantum coherence is used for neutron fields under the assumption that the complete occupation number space is a direct product of Fermi subspaces. As a result, completely coherent microfields are obtained which define a density operator in full analogy to Glauber's P representation of boson fields. For better physical significance, a transformation from the P representation to a momentum representation is performed. It is proved that the second-order coherence function in this representation is equivalent to Wolf's second-order coherence function of a classical Dirac field. Finally, the results of the theory are used to calculate explicitly the second-order coherence function and the coherence time of an ideally collimated neutron beam.

E. Ledinegg and E. Schachinger

1983-05-01T23:59:59.000Z

206

Graphene surface emitting terahertz laser: Diffusion pumping concept  

SciTech Connect

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

207

Ultrafast population dynamics in electrically modulated terahertz quantum cascade lasers  

Science Journals Connector (OSTI)

The ultrafast population dynamics in electrically modulated three-well terahertz quantum cascade lasers (QCLs) is studied by using the self-consistent Bloch–Poisson equations. In the modulation process, the non-equilibrium oscillations of the population inversion are found before the population equilibrium recovers. The equilibrium formation time increases nonlinearly with the period number. This phenomenon stems from the non-uniform distribution of the electric potential. In different periods, different responses to the electrical modulation are also explored. An in-depth understanding of electron transport in the cascade structure is obtained. Finally, we demonstrate the feasibility of a modulation frequency up to gigahertz in terahertz QCLs.

F Wang; X G Guo; C Wang; J C Cao

2013-01-01T23:59:59.000Z

208

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

209

A calculation of the temperature of contact surfaces in a high-power discharge of electric current of commercial frequency  

Science Journals Connector (OSTI)

Thermal processes occuring at the surface of disconnected electric contacts subjected to a high-power electric arc are considered.

I. L. Shleifman

1970-05-01T23:59:59.000Z

210

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

211

Coherent Expanded-Aerogels  

Science Journals Connector (OSTI)

Coherent Expanded-Aerogels ... Hydrophobization of Silica Aerogels: Insights from Quantitative Solid-State NMR Spectroscopy ... Hydrophobization of Silica Aerogels: Insights from Quantitative Solid-State NMR Spectroscopy ...

S. S. Kistler

1931-01-01T23:59:59.000Z

212

Coherence-induced entanglement  

Science Journals Connector (OSTI)

We show how atomic coherence can lead to entanglement between two thermal fields at a temperature T. We first show that the passage of a three-level atom in V configuration without coherence cannot create entanglement. However, if the excited states are driven by a microwave field, the resulting atomic coherence can lead to entanglement between the thermal fields. We show that, no matter how high the temperature of the fields is, the thermal fields can always be entangled in the presence of atomic coherence.

Fu-li Li; Han Xiong; M. Suhail Zubairy

2005-07-19T23:59:59.000Z

213

Nice, Cte d'Azur, France, 27-29 September 2006 THERMAL MODELING OF HIGH POWER LED MODULES  

E-Print Network (OSTI)

Nice, Côte d'Azur, France, 27-29 September 2006 THERMAL MODELING OF HIGH POWER LED MODULES D a study of accuracy issues in thermal modeling of high power LED modules on system level. Both physical dynamics (CFD) model of a high power LED module model at a reference application condition, and to validate

Paris-Sud XI, Université de

214

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

215

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

216

Coherence vortices in Mie scattered nonparaxial partially coherent beams  

Science Journals Connector (OSTI)

We have previously demonstrated that Mie scattering of partially coherent plane waves can create coherence vortices, namely screw-type dislocations in the phase of the spectral degree...

Marasinghe, Madara L; Premaratne, Malin; Paganin, David M; Alonso, Miguel A

2012-01-01T23:59:59.000Z

217

Reverse Coherent Information  

Science Journals Connector (OSTI)

In this Letter we define a family of entanglement distribution protocols assisted by feedback classical communication that gives an operational interpretation to reverse coherent information, i.e., the symmetric counterpart of the well-known coherent information. This leads to the definition of a new entanglement distribution capacity that exceeds the unassisted capacity for some interesting channels.

Raúl García-Patrón; Stefano Pirandola; Seth Lloyd; Jeffrey H. Shapiro

2009-05-29T23:59:59.000Z

218

High power  

Science Journals Connector (OSTI)

... 1970s technomanic projects such as nuclear power stations were still in vogue. Environmentalists argued that solar power seemed a far safer, cheaper and reassuringly low-tech power source. The technomaniacs ... tech power source. The technomaniacs, fearing that they were losingthis argument, sought to hijack solar power themselves. They proposed an enormously expensive and complicated ...

David Jones

1994-03-03T23:59:59.000Z

219

All–optoelectronic continuous–wave terahertz systems  

Science Journals Connector (OSTI)

...generation of far-infrared radiation and its applications organized...continuous-wave terahertz (THz) radiation by the mixing of visible...recent developments of THz radiation sources in the quest for increased...Nippon Steel Corporation, Japan, is acknowledged for its partial...

2004-01-01T23:59:59.000Z

220

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

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

Bandstructure and electronic states in terahertz quantum cascade lasers  

Science Journals Connector (OSTI)

Bandstructure and electron eigenstates in terahertz Quantum Cascade Lasers (QCLs) are studied by using the Quantum Transmitting Boundary Method (QTBM). It has several advantages compared to the commonly used Transfer Matrix Method (TMM). ... Keywords: QCL, QTBM, TMM, bandstructure, electron eigenstates, nanoscale technology, nanotechnology, quantum cascade lasers, quantum transmitting boundary methods, transfer matrix methods

Jing Tao Lu; Jun Cheng Cao

2006-06-01T23:59:59.000Z

222

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

223

Far Infrared and Terahertz at the turning point of change!  

E-Print Network (OSTI)

Systems NDE efforts with NASALangley · LM Michoud Shuttle External Tank foam inspection problem · Picometrix TRay 2000 sensor · Foam Void/Crack detection · Aircraft NDE/NDI Manufacturing and Maintenance · F Martin Corporation All Rights Reserved #12;Terahertz NDE of Shuttle Tank Foam Void and Cracks Found

Van Stryland, Eric

224

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

225

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

SciTech Connect

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

226

High-Power Electrodes for Lithium-Ion Batteries | U.S. DOE Office of  

Office of Science (SC) Website

High-Power Electrodes for Lithium-Ion High-Power Electrodes for Lithium-Ion Batteries Energy Frontier Research Centers (EFRCs) EFRCs Home Centers Research Science Highlights Highlight Archives News & Events Publications Contact BES Home 04.27.12 High-Power Electrodes for Lithium-Ion Batteries Print Text Size: A A A RSS Feeds FeedbackShare Page Scientific Achievement For novel 3-D anodes made of sheets of carbon (graphene) and silicon nanoparticles, transport studies found much shorter lithium diffusion paths throughout the electrode and fast lithiation/delithiation of the nanoparticles. Significance and Impact This anode design holds a greater charge than conventional lithium-ion anodes and charges/discharges more rapidly while maintaining mechanical stability. Research Details Electrochemical studies: 83% of theoretical capacity (3200 mAh g-1)

227

FY2001 Highlights Report for the Vehicle High-Power Energy Storage Program  

NLE Websites -- All DOE Office Websites (Extended Search)

HIGH-POWER HIGH-POWER ENERGY STORAGE 2 0 0 1 A N N U A L P R O G R E S S R E P O R T U.S. Department of Energy Energy Efficiency and Renewable Energy Office of Transportation Technologies A C K N O W L E D G E M E N T We would like to express our sincere appreciation to Argonne National Laboratory and to Sentech, Inc., for their artistic and technical contributions in preparing and publishing this report. In addition, we would like to thank all our program participants for their contributions to the programs and all the authors who prepared the project abstracts that comprise this report. U.S. Department of Energy Office of Advanced Automotive Technologies 1000 Independence Ave., S.W. Washington, DC 20585-0121 FY 2001 Highlights Report for the Vehicle High-Power Energy Storage Program Energy Efficiency and Renewable Energy

228

Space reactor/Stirling cycle systems for high power Lunar applications  

SciTech Connect

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

229

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

230

Measuring PM Distribution in a Catalyzed Particulate Filter using a Terahertz Wave Scanner  

Energy.gov (U.S. Department of Energy (DOE))

Terahertz scanning system produced 3-dimensional image of local PM density in catatalyzed particulate filters tested under loading and oxidizing conditions

231

Coherence Holography and Spatial Frequency Comb for 3-D Coherence Imaging and Coherence Vortex Generation  

Science Journals Connector (OSTI)

The principle and the applications of a recently proposed unconventional holography technique, coherence holography, applied for coherence vortex generation, and a related technique...

Takeda, Mitsuo; Wang, Wei; Duan, Zhihui; Miyamoto, Yoko; Rosen, Joseph

232

A Far-infrared Undulator for Coherent Synchrotron Radiation and Free Electron Laser at Tohoku University  

SciTech Connect

In order to develop an intense far-infrared radiation source, a high quality electron beam has been studied at Tohoku University, Sendai. The bunch length of the beam expected is very much shorter than terahertz (THz) wavelength, so that coherent spontaneous emission of synchrotron radiation will be a promising high brilliant far-infrared source. An undulator consisting of permanent magnets has been designed in which optional free electron laser (FEL) will be operated in free space mode. Consequently the minimum gap of the undulator is decided to be 54 mm for 0.36 mm radiation to avoid diffraction loss, and then the period length of 10 cm is employed. The undulator may cover a wavelength range from 0.18 to 0.36 mm with the beam energy of 17 MeV. Property of coherent THz radiation from the undulator and possibility of novel pre-bunched THz FEL is discussed.

Hama, Hiroyuki; Hinode, Fujio; Kawai, Masayuki; Nanbu, Kenichi; Miyahara, Fusashi; Yasuda, Mafuyu [Laboratory of Nuclear Science, Tohoku University School of Science, 1-2-1 Mikamine, Taihaku-ku, Sendai 982-0826 (Japan)

2010-06-23T23:59:59.000Z

233

Characterizing quantum coherence  

Science Journals Connector (OSTI)

For a system with canonical variables x and p, [x,p]=i?, we associate with each density operator ? an x coherence ?x and a p coherence ?p which specify, respectively, the characteristic distance and momentum range over which the underlying quantum-mechanical nature of the ensemble cannot be neglected. These coherences are less than or equal to the associated uncertainties ?x??x, ?p??p; so the ratios cx??x/?x, cp??p/?p give measures of the quantum character of the ensemble with respect to x and p. Examples are presented.

J. E. Sipe and N. Arkani-Hamed

1992-09-01T23:59:59.000Z

234

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

235

POST-IRRADIATION PROPERTIES OF CANDIDATE MATERIALS FOR HIGH POWER TARGETS  

E-Print Network (OSTI)

POST-IRRADIATION PROPERTIES OF CANDIDATE MATERIALS FOR HIGH POWER TARGETS H. Kirk, N. Simos, P Diffusivity Resistivity Thermal Expansion (CTE) Integrated Effects Shock absorption Is Carbon CTE composite that may potentially minimize thermal shock and survive high intensity pulses. Graphite

McDonald, Kirk

236

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

237

Analytical models of transient thermoelastic deformations of mirrors heated by high power cw laser beams  

E-Print Network (OSTI)

and are suspended in a vacuum vessel : the heat losses are only due to the thermal radiation. The resulting2243 Analytical models of transient thermoelastic deformations of mirrors heated by high power cw substrat. La distribution de température engendrée dans le substrat produit des déformations

Boyer, Edmond

238

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

239

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

240

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

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

Research on Control System of High Power DFIG Wind Power System  

Science Journals Connector (OSTI)

Compared with constant speed constant frequency wind turbine, variable speed constant frequency wind turbine has many advantages: higher efficiency of wind energy converting to electric power, absorbing gust energy, smoothly cutting into the network ... Keywords: wind power, DFIG, high power, LQR, variable speed constant frequency, constant power control

Li Jianlin; Xu Honghua

2008-12-01T23:59:59.000Z

242

Current spread and overheating of high power laser bars B. Laikhtmana)  

E-Print Network (OSTI)

-power lasers, the width of the stripe is much larger than the cladding thick- ness, and the substrate thicknessCurrent spread and overheating of high power laser bars B. Laikhtmana) Power Photonic, 214 Old 11794 Received 27 May 2003; accepted 12 January 2004 The heating of a semiconductor laser bar imbedded

243

High power, continuous-wave ytterbium-doped fiber laser tunable from 976 to 1120 nm  

E-Print Network (OSTI)

narrow linewidth double-clad fiber ring laser," Opt. Express 10(2), 139­144 (2002). 6. A. Silva, K. J. Paschotta, A. C. Tropper, and D. C. Hanna, "Ring-doped cladding-pumped single- mode three-level fiber laser, and T. Thomas, "Efficient high power Yb3þ-silica fibre laser cladding-pumped at 1064 nm," Opt. Commun

Paris-Sud XI, Université de

244

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

Energy.gov (U.S. Department of Energy (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...

245

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

246

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

E-Print Network (OSTI)

Geothermal 2.5 Wind 0.22 Solar 0.02 Coal 110 Natural Gas 107 Residential 50 Vehicle 39 Freight 40 Air 129.30am Advanced High Energy and High Power Battery Systems for Automotive Applications Khalil Amine electric drive Plug in Hybrid Electric Vehicle (P-HEVs), long range electric vehi cle (EV) and sm art grid

Levi, Anthony F. J.

247

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.

248

OPTICAL DIAGNOSTIC RESULTS FROM THE MERIT HIGH-POWER TARGET EXPERIMENT  

E-Print Network (OSTI)

to accept proton beams with multi-megawatt beam power. The core of this proposed target system consists, and the possible effect of that disruption on the mercury containment system. The MERIT experiment was designedOPTICAL DIAGNOSTIC RESULTS FROM THE MERIT HIGH-POWER TARGET EXPERIMENT H.G. Kirk , H. Park, T

McDonald, Kirk

249

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

250

Library Cache Coherence  

E-Print Network (OSTI)

Directory-based cache coherence is a popular mechanism for chip multiprocessors and multicores. The directory protocol, however, requires multicast for invalidation messages and the collection of acknowledgement messages, ...

Shim, Keun Sup

2011-05-02T23:59:59.000Z

251

Coherence-driven effects in sentence and discourse processing  

E-Print Network (OSTI)

Intersentential CoherenceDiscussion of Coherence Results . . . . . . . . . . . . . .198 B Guidelines for Coherence

Rohde, Hannah

2008-01-01T23:59:59.000Z

252

Quantitative Evaluation of Bulk and Interface Microstructures in Al-3003 Alloy Builds Made by Very High Power Ultrasonic Additive Manufacturing  

Science Journals Connector (OSTI)

Ultrasonically consolidated 3003 aluminum alloy builds were prepared with constituent tapes by using a very high power ultrasonic additive manufacturing (UAM) process. Microstructures of interface and...

Hiromichi T. Fujii; M. R. Sriraman…

2011-12-01T23:59:59.000Z

253

Performance scaling of high-power picosecond cryogenically cooled rod-type Yb:YAG multipass amplification  

Science Journals Connector (OSTI)

The performance scaling of high-power picosecond cryogenically cooled rod-type Yb:YAG multipass amplification is studied numerically, taking into account diffraction, dispersion,...

Fu, Xing; Hong, Kyung-Han; Chen, Li-Jin; Kärtner, Franz X

2013-01-01T23:59:59.000Z

254

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

255

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

256

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.

257

Far-infrared signature of animal tissues characterized by terahertz time-domain spectroscopy  

E-Print Network (OSTI)

, is observed to show very similar water absorption. Ã? 2005 Elsevier B.V. All rights reserved. PACS: 42.65.Re; 87.80.Ã?y Keywords: Terahertz time-domain spectroscopy; Animal tissue; Water content; Absorption. As the sen- sitivity of terahertz radiation to polar molecules of water is very high, biological tissues

258

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

259

Terahertz Vibrations of Crystalline Acyclic and Cyclic Diglycine: Benchmarks for London Force Correction Models  

Science Journals Connector (OSTI)

Terahertz Vibrations of Crystalline Acyclic and Cyclic Diglycine: Benchmarks for London Force Correction Models ... Terahertz spectroscopy provides unique insights into the fundamental cohesive forces contained within condensed-phase materials. ... CRC Handbook of Chemistry and Physics, 93 ed.; CRC Press/Taylor and Francis: Boca Raton, FL. ...

Thomas R. Juliano, Jr.; Timothy M. Korter

2013-09-17T23:59:59.000Z

260

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.

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

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

SciTech Connect

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

262

Tunable and collimated terahertz radiation generation by femtosecond laser pulses  

SciTech Connect

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

263

SAR image effects on coherence and coherence estimation.  

SciTech Connect

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

264

Multi-Scale Optical Coherence Tomography Imaging  

E-Print Network (OSTI)

Fourier domain optical coherence tomography and methods forspeed spectral-domain optical coherence tomography at 1.3umJ. G. (1991). Optical coherence tomography. Science, 254(

Oliveira, Michael

2014-01-01T23:59:59.000Z

265

Sandia National Laboratories: Spontaneous Coherence and Spin...  

NLE Websites -- All DOE Office Websites (Extended Search)

Spontaneous Coherence and Spin Texture Spontaneous Coherence and Spin Texture videobanner Spontaneous Coherence and Spin Texture in a Cold Exciton Gas (Watch Video) Speaker:...

266

Durability of Low Pt Fuel Cells Operating at High Power Density  

NLE Websites -- All DOE Office Websites (Extended Search)

SPIRE Program Kickoff SPIRE Program Kickoff Topic 3A. Cell Degradation Studies / Degradation Studies Durability of Low Pt Fuel Cells Operating at High Power Density US DOE Fuel Cell Projects Kickoff Meeting DOE Award: DE-EE0000469 October 1 st , 2009 Program Objectives The objective of this program is to study and identify strategies to assure durability of fuel cells designed to meet DOE cost targets. Technical Barriers Barrier Approach Strategy A. Durability Reinforced, Stabilized Membrane MEA Partner Durability-Enhanced Electrodes Electrocatalyst/MEA Partner Optimized Operating Conditions Parametric model & experimental studies B. Cost Low Pt Loadings (0.2 mg/cm 2 ) Electrocatalyst/MEA Partner High Power Density (>1.0W/cm 2 ) Open Flowfield Stack Metallic Stack Architecture Incumbent Derivative

267

PPPL delivers a plasma source that will enable high-power beam pulses in a  

NLE Websites -- All DOE Office Websites (Extended Search)

delivers a plasma source that will enable high-power beam pulses in a delivers a plasma source that will enable high-power beam pulses in a new Berkeley Lab accelerator March 19, 2012 Tweet Widget Facebook Like Google Plus One Erik Gilson with a copper-clad module and chamber for testing the units. (Photo by Elle Starkman, PPPL Office of Communications) Erik Gilson with a copper-clad module and chamber for testing the units. Gallery: Interior views of a plasma-source module. (Photo by Elle Starkman, PPPL Office of Communications) Interior views of a plasma-source module. Technician aligns plasma source with NDCX-II accelerator in background. (Photo by Elle Starkman, PPPL Office of Communications) Technician aligns plasma source with NDCX-II accelerator in background. Plainsboro, New Jersey - Scientists at the U.S. Department of Energy's

268

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

269

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

270

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

SciTech Connect

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

271

Injection locking of a high power ultraviolet laser diode for laser cooling of ytterbium atoms  

E-Print Network (OSTI)

We developed a high-power laser system at a wavelength of 399 nm for laser cooling of ytterbium atoms with ultraviolet laser diodes. The system is composed of an external cavity laser diode providing frequency stabilized output at a power of 40 mW and another laser diode for amplifying the laser power up to 220 mW by injection locking. The systematic method for optimization of our injection locking can also be applied to high power light sources at any other wavelengths. Our system, which does not depend on complex nonlinear frequency-doubling, has great importance for implementing transportable optical lattice clocks, and is also useful for investigations on condensed matter physics or quantum information processing using cold atoms.

Toshiyuki Hosoya; Martin Miranda; Ryotaro Inoue; Mikio Kozuma

2014-12-02T23:59:59.000Z

272

Thermal evaluation and performance of high-power Lithium-ion cells  

SciTech Connect

Under the sponsorship of the US Advanced Battery Consortium (USABC) and the Partnership for a New Generation of Vehicles (PNGV), Saft has developed high-power lithium-ion (Li-Ion) batteries for hybrid electric vehicles (HEVs). These high-power Li-Ion batteries are being evaluated for the US Department of Energy's (DOE) Hybrid Vehicle Propulsion Program. As part of this program, the National Renewable Energy Laboratory (NREL) characterized the thermal performance of the Saft (6-Ah) Li-Ion cells. The characterization included (1) obtaining thermal images of cells under a specified cycle, (2) measuring heat generation from the cells at various temperatures and under various charge/discharge profiles, and (3) determining the cells' capabilities for following a simulated power profile (driving cycle) at various initial states of charge and temperatures.

Keyser, M.; Pesaran, A.; Oweis, S.; Chagnon, G.; Ashtiani, C.

2000-01-25T23:59:59.000Z

273

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

SciTech Connect

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

274

Maximal Privacy without Coherence  

Science Journals Connector (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 that are too noisy to transmit any quantum information reliably that can nevertheless send private classical information. Here, we ask how much private classical information a channel can transmit if it has little quantum capacity. We present a class of channels Nd with input dimension d2, quantum capacity Q(Nd)?1, and private capacity P(Nd)=logd. These channels asymptotically saturate an interesting inequality P(N)?(1/2)[logdA+Q(N)] for any channel N with input dimension dA and capture the essence of privacy stripped of the confounding influence of coherence.

Debbie Leung; Ke Li; Graeme Smith; John A. Smolin

2014-07-16T23:59:59.000Z

275

Coherence in Microchip Traps  

Science Journals Connector (OSTI)

We report the coherent manipulation of internal states of neutral atoms in a magnetic microchip trap. Coherence lifetimes exceeding 1 s are observed with atoms at distances of 5–130????m from the microchip surface. The coherence lifetime in the chip trap is independent of atom-surface distance within our measurement accuracy and agrees well with the results of similar measurements in macroscopic magnetic traps. Because of the absence of surface-induced decoherence, a miniaturized atomic clock with a relative stability in the 10-13 range can be realized. For applications in quantum information processing, we propose to use microwave near fields in the proximity of chip wires to create potentials that depend on the internal state of the atoms.

Philipp Treutlein; Peter Hommelhoff; Tilo Steinmetz; Theodor W. Hänsch; Jakob Reichel

2004-05-21T23:59:59.000Z

276

Temperature-Dependent Battery Models for High-Power Lithium-Ion Batteries  

SciTech Connect

In this study, two battery models for a high-power lithium ion (Li-Ion) cell were compared for their use in hybrid electric vehicle simulations in support of the U.S. Department of Energy's Hybrid Electric Vehicle Program. Saft America developed the high-power Li-Ion cells as part of the U.S. Advanced Battery Consortium/U.S. Partnership for a New Generation of Vehicles programs. Based on test data, the National Renewable Energy Laboratory (NREL) developed a resistive equivalent circuit battery model for comparison with a 2-capacitance battery model from Saft. The Advanced Vehicle Simulator (ADVISOR) was used to compare the predictions of the two models over two different power cycles. The two models were also compared to and validated with experimental data for a US06 driving cycle. The experimental voltages on the US06 power cycle fell between the NREL resistive model and Saft capacitance model predictions. Generally, the predictions of the two models were reasonably close to th e experimental results; the capacitance model showed slightly better performance. Both battery models of high-power Li-Ion cells could be used in ADVISOR with confidence as accurate battery behavior is maintained during vehicle simulations.

Johnson, V.H.; Pesaran, A.A. (National Renewable Energy Laboratory); Sack, T. (Saft America)

2001-01-10T23:59:59.000Z

277

Weighted Coherence: A More Effective Measure Than Average Coherence  

Science Journals Connector (OSTI)

In this study, we evaluated the effectiveness of the statistic, “Weighted Coherence” in relation to the average or mean coherence in a particular frequency band after cross- ... using cross-spectral analysis is r...

Vikram Kumar Yeragani; Arindam Barua…

2003-12-01T23:59:59.000Z

278

Mid-infrared pump-related electric-field domains in GaAs/(Al,Ga)As quantum-cascade structures for terahertz lasing without population inversion  

SciTech Connect

We investigate the effect of mid-infrared (MIR) pumping on the transport properties of GaAs/(Al,Ga)As terahertz (THz) quantum lasers (TQLs), which rely on quantum coherence effects of intersubband transitions. Aiming at THz lasing at elevated temperatures, we extend the concept of THz gain with and without population inversion of a single, MIR-pumped, electrically driven THz stage proposed by Waldmueller et al.[Phys. Rev. Lett. 99, 117401 (2007)] to an entire TQL. However, experiments using a CO{sub 2} as well as a free-electron laser and numerical simulations show that this resonant MIR pumping causes a negative differential conductivity (NDC) in addition to the NDC caused by sequential tunneling. Lasing of these TQLs is prevented by the formation of electric-field domains below the resonance field strength for gain of each single THz stage.

Giehler, M.; Wienold, M.; Schrottke, L.; Hey, R.; Grahn, H. T. [Paul-Drude-Institut fuer Festkoerperelektronik, Hausvogteiplatz 5-7, 10117 Berlin (Germany); Pavlov, S. G. [Deutsches Zentrum fuer Luft- und Raumfahrt, Rutherfordstr. 2, 12489 Berlin (Germany); Huebers, H.-W. [Deutsches Zentrum fuer Luft- und Raumfahrt, Rutherfordstr. 2, 12489 Berlin (Germany); Institut fuer Optik und Atomare Physik, Technische Universitaet Berlin, Hardenbergstr. 36, 10623 Berlin (Germany); Winnerl, S.; Schneider, H. [Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstrasse 400, 01328 Dresden (Germany)

2011-11-15T23:59:59.000Z

279

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

280

Coherence in photoionization  

Science Journals Connector (OSTI)

We have detected coherence in a superposition of excited states by collecting photoelectrons. The superposition state is prepared by one laser pulse, and the photoelectrons are produced by a delayed laser pulse. We have described the experiment by the extension of a simple model and found the agreement with the data to be quite good.

Ting Shan Luk; Louis DiMauro; Mark Feldman; Harold Metcalf

1981-08-01T23:59:59.000Z

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.


281

Nonlinear optics at maximum coherence  

Science Journals Connector (OSTI)

...D. Walls Nonlinear optics at maximum coherence S. E. Harris G. Y. Yin M. Jain H...optical processes which utilize maximum coherence of a non-allowed transition. The nonlinear...frequency. Nonlinear optics at maximum coherence B y S. E. Harris, G. Y. Yin, M...

1997-01-01T23:59:59.000Z

282

Coherence Transfer in Magnetic Fields  

Science Journals Connector (OSTI)

Some results recently discussed by Chiu for interatomic coherence transfer are shown to have a simple physical interpretation, to be independent of collision model assumed, and to be applicable also to intra -atomic coherence transfer. A derivation using density matrices is presented which takes both depolarizing collisions and backtransfer of coherence into account.

W. E. Baylis

1973-03-01T23:59:59.000Z

283

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

284

Stimulated Terahertz Emission from Intra-Excitonic Transitions inCu2O  

SciTech Connect

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

285

Temperature dependence of plasmonic terahertz absorption in grating-gate gallium-nitride transistor structures  

Science Journals Connector (OSTI)

Strong plasmon resonances have been observed in the terahertz transmission spectra (1–5 THz) of large-area slit-grating-gate AlGaN/GaN-based high-electron-mobility transistor(HEMT) structures at temperatures from 10 to 170 K. The resonance frequencies correspond to the excitation of plasmons with wave vectors equal to the reciprocal lattice vectors of the metal grating which serves both as a gate electrode for the HEMT and a coupler between plasmons and incident terahertz radiation. Wide tunability of the resonances by the applied gate voltage demonstrates potential of these devices for terahertz applications.

A. V. Muravjov; D. B. Veksler; V. V. Popov; O. V. Polischuk; N. Pala; X. Hu; R. Gaska; H. Saxena; R. E. Peale; M. S. Shur

2010-01-01T23:59:59.000Z

286

Deposition of Pt inside fuel cell electrodes using high power impulse magnetron sputtering  

Science Journals Connector (OSTI)

The high power impulse magnetron sputtering (HiPIMS) process is used to incorporate catalytic nanoclusters of platinum into microporous carbon. Such a process leads to an enhancement of the Pt species' penetration into the porous medium, as evidenced by Rutherford backscattering spectroscopy analysis. Each sample of catalyzed porous carbon is tested as a cathode of a proton exchange membrane fuel cell (PEMFC). An increase of 80% at 0.65 V of the PEMFC power density for a low catalyst loading of 0.02 mg cm?2 highlights the use of the HiPIMS process versus the conventional dc magnetron sputtering process.

S Cuynet; A Caillard; T Lecas; J Bigarré; P Buvat; P Brault

2014-01-01T23:59:59.000Z

287

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

SciTech Connect

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

288

A novel high power density permanent magnet variable-speed motor  

SciTech Connect

This paper proposes a novel polyphase multipole permanent magnet motor which possesses high power density, high efficiency and excellent controllability, yet can be produced by conventional fabrication technique. The basic operating principles, design features, performance analysis and control system are described. The experimental results of a 5 kW, 1,500 rpm prototype motor and its comparison with other types of motors such as switched reluctance motor and induction motor are given. This proposed motor has the potential to compete in certain applications.

Chan, C.C.; Chen, G.H.; Jiang, J.Z.; Wang, X.Y. (Univ. of Hong Kong (Hong Kong))

1993-06-01T23:59:59.000Z

289

Modeling of dimmable High Power LED illumination distribution using ANFIS on the isolated area  

Science Journals Connector (OSTI)

High power light emitting diodes (HP-LEDs) are more suitable for energy saving applications and have becoming replacing traditional fluorescent and incandescent bulbs for its energy efficient. Therefore, HP-LED lighting has been regarded in the next-generation lighting. In this study, illumination distribution of white color HP-LED is modeled by adaptive neuro-fuzzy inference system (ANFIS) approach on the isolated area while LED head is fixed. Subtractive clustering with hybrid learning approach is used to train the realized ANFIS architectures. End of the numerous experiment we finally concluded that, ANFIS could be used to modeling the illumination distribution applications perfectly.

?smail Kiyak; Vedat Topuz; Bülent Oral

2011-01-01T23:59:59.000Z

290

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

SciTech Connect

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

291

Microwave power thin film resistors for high frequency and high power load applications  

Science Journals Connector (OSTI)

The authors report a power-dividing-based microwave power thin film resistor (MPTFR) that exhibits high operating frequency and high power load. The MPTFR is comprised of substrate ground electrodes two TaN resistive films power dividing circuit and signal input port. The experimental results show that the voltage standing wave ratio of the MPTFR is lower than 1.6 in the band of 3.4–7.4 GHz and 8.2–9.8 GHz. The power load of the MPTFR is 200 W. The experimental data are in good agreement with the electromagnetic simulations.

H. C. Jiang; X. Si; W. L. Zhang; C. J. Wang; B. Peng; Y. R. Li

2010-01-01T23:59:59.000Z

292

Diversion assumptions for high-powered research reactors. ISPO C-50 Phase 1  

SciTech Connect

This study deals with diversion assumptions for high-powered research reactors -- specifically, MTR fuel; pool- or tank-type research reactors with light-water moderator; and water, beryllium, or graphite reflectors, and which have a power level of 25 MW(t) or more. The objective is to provide assistance to the IAEA in documentation of criteria and inspection observables related to undeclared plutonium production in the reactors described above, including: criteria for undeclared plutonium production, necessary design information for implementation of these criteria, verification guidelines including neutron physics and heat transfer, and safeguards measures to facilitate the detection of undeclared plutonium production at large research reactors.

Binford, F.T.

1984-01-01T23:59:59.000Z

293

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

SciTech Connect

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

294

Spectroscopic imaging of self-organization in high power impulse magnetron sputtering plasmas  

SciTech Connect

Excitation and ionization conditions in traveling ionization zones of high power impulse magnetron sputtering plasmas were investigated using fast camera imaging through interference filters. The images, taken in end-on and side-on views using light of selected gas and target atom and ion spectral lines, suggest that ionization zones are regions of enhanced densities of electrons, and excited atoms and ions. Excited atoms and ions of the target material (Al) are strongly concentrated near the target surface. Images from the highest excitation energies exhibit the most localized regions, suggesting localized Ohmic heating consistent with double layer formation.

Andersson, Joakim [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720 (United States) [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720 (United States); Centre for Quantum Technologies, National University of Singapore, 3 Science Drive 2, 117543 Singapore (Singapore); Ni, Pavel; Anders, André [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720 (United States)] [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720 (United States)

2013-07-29T23:59:59.000Z

295

The capacitively coupled converter (C³) for high power DC-DC conversion  

E-Print Network (OSTI)

5 11 12 14 17 17 25 26 27 29 29 42 45 48 48 51 51 CHAPTER VI ANALYSIS OF C' USING S. SPACEAVERAGING . . The General Converter. . . The C Coupling Capacitor Voltage VI S~RY AND CONCLUSION . Suitability for High Power... signal transient for flyback capacitor voltageVci for special case of starting with fixed D, fixed T, and lower voltage threshold over-ride . . . . 52 5-3 Large signal transient for input inductor current for example in figure 5-2 . 53 5-4 Large signal...

Khan, Shahriar

2012-06-07T23:59:59.000Z

296

Quantum correlation via quantum coherence  

E-Print Network (OSTI)

Quantum correlation includes quantum entanglement and quantum discord. Both entanglement and discord have a common necessary condition--------quantum coherence or quantum superposition. In this paper, we attempt to give an alternative understanding of how quantum correlation is related to quantum coherence. We divide the coherence of a quantum state into several classes and find the complete coincidence between geometric (symmetric and asymmetric) quantum discords and some particular classes of quantum coherence. We propose a revised measure for total coherence and find that this measure can lead to a symmetric version of geometric quantum correlation which is analytic for two qubits. In particular, this measure can also arrive at a monogamy equality on the distribution of quantum coherence. Finally, we also quantify a remaining type of quantum coherence and find that for two qubits it is directly connected with quantum nonlocality.

Chang-shui Yu; Yang Zhang; Haiqing Zhao

2014-02-19T23:59:59.000Z

297

Photocurrent-based detection of terahertz radiation in graphene  

SciTech Connect

Graphene is a promising candidate for the development of detectors of Terahertz (THz) radiation. A well-known detection scheme due to Dyakonov and Shur exploits plasma waves in a field-effect transistor (FET), whereby a dc photovoltage is generated in response to a THz field. In the quest for devices with a better signal-to-noise ratio, we theoretically investigate a plasma-wave photodetector in which a dc photocurrent is generated in a graphene FET. The noise equivalent power of our device is shown to be much smaller than that of a Dyakonov-Shur detector in a wide spectral range.

Tomadin, Andrea, E-mail: andrea.tomadin@sns.it; Tredicucci, Alessandro; Vitiello, Miriam S.; Polini, Marco [NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, I-56126 Pisa (Italy)] [NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, I-56126 Pisa (Italy); Pellegrini, Vittorio [NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, I-56126 Pisa (Italy) [NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, I-56126 Pisa (Italy); Istituto Italiano di Tecnologia (IIT), Via Morego 30, 16163 Genova (Italy)

2013-11-18T23:59:59.000Z

298

Analysis of electromagnetic modes excited in overmoded structure terahertz source  

SciTech Connect

A method on electromagnetic mode analysis in overmoded structure terahertz source is studied in this paper. This mode analysis method is based on Fourier-Bessel series and the particle-in-cell simulation. The result of mode analysis shows that there are TM{sub 02} and TM{sub 03} modes present in the waveguide motivated by mode change in the discontinuity. The mode content keeps stable when the device starts to work. The magnetic field and the voltage of beam do not change the mode content to some extent. The parameters of diode affect the mode content significantly.

Li, Xiaoze; Xiao, Renzhen; Wang, Guangqiang; Zhang, Lijun; Zhang, Yuchuan; Ye, Hu [Northwest Institute of Nuclear Technology, P. O. Box 69-1, Xi'an 710024 (China)] [Northwest Institute of Nuclear Technology, P. O. Box 69-1, Xi'an 710024 (China); Wang, Jianguo [Northwest Institute of Nuclear Technology, P. O. Box 69-1, Xi'an 710024 (China) [Northwest Institute of Nuclear Technology, P. O. Box 69-1, Xi'an 710024 (China); School of Electronic and Information Engineering, Xi'an Jiaotong University, Xi'an 710049 (China)

2013-08-15T23:59:59.000Z

299

Efficient Cherenkov emission of broadband terahertz radiation from an ultrashort laser pulse in a sandwich structure with nonlinear core  

SciTech Connect

A scheme for efficient generation of broadband terahertz radiation by a femtosecond laser pulse propagating in a planar sandwichlike structure is proposed. The structure consists of a thin nonlinear core cladded with prisms made of a material with low terahertz absorption. The focused into a line laser pulse propagates in the core as a leaky or waveguide mode and emits Cherenkov wedge of terahertz waves in the cladding. We developed a theory that describes terahertz generation in such a structure and calculated spatial distribution of the generated terahertz field, its energy spectrum and optical-to-terahertz conversion efficiency. The developed theory predicts the conversion efficiency of up to several percent in a 1 cm long and 1 cm wide Si-LiNbO{sub 3}-Si sandwich structure with a 20 {mu}m thick nonlinear layer pumped by 8.5 {mu}J Ti:sapphire laser with pulse duration of 100 fs.

Bodrov, S. B. [Institute of Applied Physics, Russian Academy of Sciences, Nizhny Novgorod 603950 (Russian Federation); University of Nizhny Novgorod, Nizhny Novgorod 603950 (Russian Federation); Bakunov, M. I. [University of Nizhny Novgorod, Nizhny Novgorod 603950 (Russian Federation); Institute of Applied Physics, Russian Academy of Sciences, Nizhny Novgorod 603950 (Russian Federation); Hangyo, M. [Laser Terahertz Division, Institute of Laser Engineering, Osaka University, Osaka (Japan)

2008-11-01T23:59:59.000Z

300

Coherence Controlled Soliton Interactions  

Science Journals Connector (OSTI)

We demonstrate theoretically and subsequently observe in experiment a novel type of soliton interaction when a pair of closely spaced spatial optical solitons as a whole is made partially incoherent. We explain how the character of the soliton interaction can be controlled by the total partial incoherence, and show a possibility to change the soliton interaction from attractive to repulsive, or vice versa, near a certain threshold in the coherence parameter.

Ting-Sen Ku; Ming-Feng Shih; Andrey A. Sukhorukov; Yuri S. Kivshar

2005-02-18T23:59:59.000Z

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.


301

Breakdown of Coherence ?  

E-Print Network (OSTI)

In a recent paper, Albrecht Kyrieleis, Jeff Forshaw and I discovered a new tower of super-leading logarithms in gaps between jets cross sections. After discussions with the referee of our paper and further investigation, we have come to view this as a breakdown of naive coherence for initial state radiation. In this talk I illustrate this statement in a simple way, and show how it results in the super-leading logarithms.

Michael H. Seymour

2007-10-15T23:59:59.000Z

302

High-power LEDs based on InGaAsP/InP heterostructures  

SciTech Connect

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

303

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

SciTech Connect

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

304

System efficiency analysis for high power solid state radio frequency transmitter  

SciTech Connect

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

305

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

SciTech Connect

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

306

High power millimeter wave experiment of ITER relevant electron cyclotron heating and current drive system  

SciTech Connect

High power, long pulse millimeter (mm) wave experiments of the RF test stand (RFTS) of Japan Atomic Energy Agency (JAEA) were performed. The system consists of a 1 MW/170 GHz gyrotron, a long and short distance transmission line (TL), and an equatorial launcher (EL) mock-up. The RFTS has an ITER-relevant configuration, i.e., consisted by a 1 MW-170 GHz gyrotron, a mm wave TL, and an EL mock-up. The TL is composed of a matching optics unit, evacuated circular corrugated waveguides, 6-miter bends, an in-line waveguide switch, and an isolation valve. The EL-mock-up is fabricated according to the current design of the ITER launcher. The Gaussian-like beam radiation with the steering capability of 20 deg. - 40 deg. from the EL mock-up was also successfully proved. The high power, long pulse power transmission test was conducted with the metallic load replaced by the EL mock-up, and the transmission of 1 MW/800 s and 0.5 MW/1000 s was successfully demonstrated with no arcing and no damages. The transmission efficiency of the TL was 96%. The results prove the feasibility of the ITER electron cyclotron heating and current drive system.

Takahashi, K.; Kajiwara, K.; Oda, Y.; Kasugai, A.; Kobayashi, N.; Sakamoto, K. [Japan Atomic Energy Agency, 801-1 Mukoyama, Naka, Ibaraki 311-0193 (Japan); Doane, J.; Olstad, R. [General Atomics, P.O. Box 85608, San Diego, California 92186-5608 (United States); Henderson, M. [ITER Organization, CS90 046, 13067 St. Paul lez Durance Cedex (France)

2011-06-15T23:59:59.000Z

307

Thermal Transients During Processing of 3003 Al-H18 Multilayer Build by Very High-Power Ultrasonic Additive Manufacturing  

Science Journals Connector (OSTI)

Previous investigations suggested a gradient in bond microstructure along the height of a “build” made by very high power ultrasonic additive manufacturing—a rapid prototyping process that is based...

M. R. Sriraman; Matt Gonser; Daniel Foster…

2012-02-01T23:59:59.000Z

308

Highly efficient, high-power, broadly tunable, cryogenically cooled and diode-pumped Yb:CaF2  

Science Journals Connector (OSTI)

We present a high-power diode-pumped Yb:CaF2 laser operating at cryogenic temperature (77K). A laser output power of 97W at 1034nm was extracted for a pump power of 245W....

Ricaud, S; Papadopoulos, D N; Camy, P; Doualan, J L; Moncorgé, R; Courjaud, A; Mottay, E; Georges, P; Druon, F

2010-01-01T23:59:59.000Z

309

Nd:GdVO4 in Face-Cooled Geometries: Thin-Disk and High-Power Microchip Lasers  

Science Journals Connector (OSTI)

The potential of Nd:GdVO4 for face-cooled geometries is discussed. Particular emphasis is given to experimental and finite element studies of thin-disk and high-power, monolithic,...

Kemp, Alan J; Valentine, Gareth J; Burns, David

310

High-power diode-pumped cryogenically cooled Yb:CaF2 laser with extremely low quantum defect  

Science Journals Connector (OSTI)

High-power diode-pumped laser operation at 992–993?nm under a pumping wavelength of 981 of 986?nm is demonstrated with Yb:CaF2 operating at cryogenic temperature (77?K),...

Ricaud, S; Papadopoulos, D N; Pellegrina, A; Balembois, F; Georges, P; Courjaud, A; Camy, P; Doualan, J L; Moncorgé, R; Druon, F

2011-01-01T23:59:59.000Z

311

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

312

Broadly tunable high-power operation of an all-solid-state titanium-doped sapphire laser system  

Science Journals Connector (OSTI)

Broadly tunable and high-power operation of a titanium-doped sapphire laser is obtained with a diode-laser-pumped frequency-doubled Nd:YAG laser as the pump source. A maximum broadband...

Steele, T R; Gerstenberger, D C; Drobshoff, A; Wallace, R W

1991-01-01T23:59:59.000Z

313

Using Terahertz Time-Domain Spectroscopy to Determine the Glass Transition Temperature of Heavy Oils  

Science Journals Connector (OSTI)

Terahertz time-domain spectroscopy is used to measure the temperature-dependent refractive index of heavy oils down to 80 K. Evidence for a glass transition is observed, providing...

Ayesheshim, Ayesheshim; Titova, Lyubov; Wang, Zhenyou; Kabir, Amin; Indo, Kentaro; Abivin, Patrice; Taylor, Shawn; Cheng, Yuesheng; Hegmann, Frank

314

Time Domain Terahertz Non Destructive Evaluation of Water Intrusion in Composites and Corrosion under Insulation  

Science Journals Connector (OSTI)

Time domain terahertz (a.k.a. T-Ray or THz) imaging is used to detect water intrusion and delamination in composite structures used in radomes. Corrosion is detected on pipes beneath...

White, Jeffrey S; Zimdars, David A

315

Graphene based tunable metamaterial absorber and polarization modulation in terahertz frequency  

Science Journals Connector (OSTI)

Graphene can be utilized in designing tunable terahertz devices due to its tunability of sheet conductivity. In this paper, we combine the metamaterial having unit cell of cross-shaped...

Zhang, Yin; Feng, Yijun; Zhu, Bo; Zhao, Junming; Jiang, Tian

2014-01-01T23:59:59.000Z

316

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

SciTech Connect

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

317

Graphene-based tunable terahertz and infrared band-pass filter  

Science Journals Connector (OSTI)

This paper presents a sheet of graphene as a simple band-pass filter in terahertz and infrared frequencies. The central frequency and quality factor of this band-pass filter can be...

Danaeifar, M; Granpayeh, N; Mohammadi, A; Setayesh, A

2013-01-01T23:59:59.000Z

318

Near-Infrared Laser Pulse Induced Amplitude Modulation of Terahertz Quantum Cascade Lasers  

Science Journals Connector (OSTI)

We have demonstrated amplitude modulation of terahertz quantum cascade lasers by means of the injection of near-infrared laser pulses. Injected 770nm and 1350nm laser pulses both...

Sakasegawa, Yohei; Saito, Shingo; Sekine, Norihiko; Ashida, Masaaki; Hosako, Iwao

319

The Influence of Doping on the Performance of Terahertz Quantum-Cascade-Lasers  

Science Journals Connector (OSTI)

We present the effects of the doping concentration on a set of terahertz quantum-cascade-lasers emitting around 2.75 THz. The threshold current density decreases linearly with the...

Benz, Alexander; Fasching, Gernot; Andrews, Aaron Maxwell; Unterrainer, Karl; Roch, Tomas; Schrenk, Werner; Strasser, Gottfried

320

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

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

Coherent photoelectron bunch generation and quantum efficiency enhancement in a photocathode optical resonator  

Science Journals Connector (OSTI)

A novel scheme producing multiple coherently phased high charge (nC) short duration (ps) electron bunches in a radio?frequency (rf) photoinjector is presented. In this configuration the mirrorphotocathode is an integral part of an optical resonator. The ultrashort laser pulse is reflected off the photocathode and recirculated through the optical cavity at a subharmonic of the rf drive frequency after extracting a photoelectron bunch. This new technique can dramatically increase the effective quantum efficiency of metals and produce high current high brightness prebunched electron beams ideally suited for high power coherent microwave generation. A proof?of?principle experiment operating at 0.250 GHz and using a frequency?quadrupled mode?locked Nd:YAG laser has shown the production of a train of coherently phased photoelectron bunches with a measured effective quantum efficiency enhancement of 4.2.

F. V. Hartemann; S. N. Fochs; J. D. McNally; S. Burns; N. C. Luhmann Jr.; M. D. Perry; K. R. Chu

1994-01-01T23:59:59.000Z

322

IEEE PHOTONICS TECHNOLOGY LETTERS 1 High-Power 2.3-m GaSb-Based Linear Laser Array  

E-Print Network (OSTI)

2.3-m laser. Al Ga As Sb cladding layers. Details of the lasers' heterostructure design can be foundIEEE PHOTONICS TECHNOLOGY LETTERS 1 High-Power 2.3-m GaSb-Based Linear Laser Array L. Shterengas, G--High-power 2.3- m In(Al)GaAsSb­GaSb type-I double quantum-well diode laser arrays were fabricated

323

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

324

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

SciTech Connect

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

325

Self-Heterodyne Spectrometer Using Uni-Traveling-Carrier Photodiodes for Terahertz-Wave Generators and Optoelectronic Mixers  

Science Journals Connector (OSTI)

We demonstrate a self-heterodyne terahertz (THz) frequency-domain spectrometer in which commercially available uni-traveling-carrier photodiodes (UTC-PDs) are used as...

Hisatake, Shintaro; Kim, Jae-Young; Ajito, Katsuhiro; Nagatsuma, Tadao

2014-01-01T23:59:59.000Z

326

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

327

Development of a High-Power Coaxial Pulse Tube Refrigerator for a Liquid Xenon Calorimeter  

SciTech Connect

A high-power coaxial pulse tube refrigerator has been designed, fabricated and tested to meet the requirements of liquefaction and re-condensation of xenon gas for a large liquid xenon calorimeter. A feature of this pulse tube refrigerator is that a cylindrical regenerator placed inside of the pulse tube for space saving and easy fabrication. It provides a cooling power of 70 W at 165 K by using a 2.2 kW GM-type compressor. The cooling power performance up to 120 W using a much larger compressor was also tested. The outer cylinder is a stainless steel pipe of 60 mm diameter, 180 mm in length and 0.5 mm in thickness. The regenerator consists of about 900 disk sheets of no. 300 stainless steel mesh packed in a Bakelite tube.

Haruyama, T.; Kasami, K.; Inoue, H. [KEK, High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Mihara, S. [ICEPP, International Center for Elementary Particle Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033 (Japan); Matsubara, Y. [Nihon University, 7-24-1 Narashinodai, Funabashi, Chiba 274-8501 (Japan)

2004-06-23T23:59:59.000Z

328

Time Structure of Particle Production in the MERIT High-Power Target Experiment  

SciTech Connect

The MERIT experiment is a proof-of-principle test of a target system for high power proton beam to be used as front-end for a neutrino factory complex or amuon collider. The experiment took data in autumn 2007 with the fast extracted beam from the CERN Proton Synchrotron (PS) to a maximum intensity of about 30 x 10{sup 12} protons per pulse. We report results from the portion of the MERIT experiment in which separated beam pulses were delivered to a free mercury jet target with time intervals between pulses varying from 2 to 700 {micro}s. The analysis is based on the responses of particle detectors placed along side and downstream of the target.

Efthymiopoulos, I.; Fabich, A.; Palm, M.; Lettry, J.; Haug, F.; Pereira, H.; Pernegger, H.; Steerenberg, R.; Grudiev, A.; /CERN; Kirk, H.G.; Park, H.; /Brookhaven /Fermilab /Oak Ridge /Princeton U. /Rutherford

2009-05-01T23:59:59.000Z

329

Coulomb explosion effect and the maximum energy of protons accelerated by high-power lasers  

Science Journals Connector (OSTI)

The acceleration of light ions (protons) through the interaction of a high-power laser pulse with a double-layer target is theoretically studied by means of two-dimensional particle-in-cell simulations and a one-dimensional analytical model. It is shown that the maximum energy acquired by the accelerated light ions (protons) depends on the physical characteristics of a heavy-ion layer (electron-ion mass ratio and effective charge state of the ions). In our theoretical model, the hydrodynamic equations for both electron and heavy-ion species are solved and the test-particle approximation for the light ions (protons) is applied. The heavy-ion motion is found to modify the longitudinal electric field distribution, thus changing the acceleration conditions for the protons.

E. Fourkal; I. Velchev; C.-M. Ma

2005-03-25T23:59:59.000Z

330

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

331

Grating formation by a high power radio wave in near-equator ionosphere  

SciTech Connect

The formation of a volume grating in the near-equator regions of ionosphere due to a high power radio wave is investigated. The radio wave, launched from a ground based transmitter, forms a standing wave pattern below the critical layer, heating the electrons in a space periodic manner. The thermal conduction along the magnetic lines of force inhibits the rise in electron temperature, limiting the efficacy of heating to within a latitude of few degrees around the equator. The space periodic electron partial pressure leads to ambipolar diffusion creating a space periodic density ripple with wave vector along the vertical. Such a volume grating is effective to cause strong reflection of radio waves at a frequency one order of magnitude higher than the maximum plasma frequency in the ionosphere. Linearly mode converted plasma wave could scatter even higher frequency radio waves.

Singh, Rohtash; Sharma, A. K.; Tripathi, V. K. [Department of Physics, Indian Institute of Technology Delhi, New Delhi-110016 (India)

2011-11-15T23:59:59.000Z

332

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

SciTech Connect

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

333

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

SciTech Connect

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

334

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

335

Philips Lumileds Develops a Low-Cost, High-Power, Warm-White LED Package  

Energy.gov (U.S. Department of Energy (DOE))

With the help of DOE funding, Philips Lumileds has developed a low-cost, high-power, warm-white LED package for general illumination. During the course of the two-year project, this package was used to commercialize a series of products with correlated color temperatures (CCTs) ranging from 2700 to 5700 K, under the product name LUXEON M. A record efficacy of nearly 125 lm/W was demonstrated at a flux of 1023 lumens, a CCT of 3435 K, and a color rendering index (CRI) of more than 80 at room temperature in the productized package. In an R&D package, a record efficacy of more than 133 lm/W at a flux of 1015 lumens, a CCT of 3475 K, and a CRI greater than 80 at room temperature were demonstrated.

336

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

SciTech Connect

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

337

FY2000 Highlights Report for the Vehicle High-Power Energy Storage Program  

NLE Websites -- All DOE Office Websites (Extended Search)

Energy Energy Office of Advanced Automotive Technologies 1000 Independence Avenue, S.W. Washington, DC 20585-0121 FY 2000 Highlights Report for the Vehicle High-Power Energy Storage Program Energy Efficiency and Renewable Energy Office of Transportation Technologies Office of Advanced Automotive Technologies Energy Management Team Raymond A. Sutula Energy Management Team Leader November 2000 This document highlights work sponsored by agencies of the U.S. Government. Neither the U.S. Government nor any agency, thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe

338

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

339

Quantum Privacy and Quantum Coherence  

Science Journals Connector (OSTI)

We derive a simple relation between a quantum channel's capacity to convey coherent (quantum) information and its usefulness for quantum cryptography.

Benjamin Schumacher and Michael D. Westmoreland

1998-06-22T23:59:59.000Z

340

Phase correlations and optical coherence  

Science Journals Connector (OSTI)

We examine the properties of the recently introduced degrees of coherence regarding the phase correlations of the optical field. It is seen that some of these quantities are...

Tervo, Jani; Setälä, Tero; Friberg, Ari T

2012-01-01T23:59:59.000Z

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.


341

Coherence-induced entanglement  

E-Print Network (OSTI)

and these transitions are coupled resonantly with the asteriskmathReprinted with permission from Fuli Li, Han Xiong and M. Suhail Zubairy, Phys. Rev. A 72, 010303, (2005). Copyright (2005) by the American Physical Society. ?Readers may view, browse, and/or download... Zubairy Marlan O. Scully Committee Members, George R. Welch Goong Chen Head of Department, Edward Fry May 2006 Major Subject: Physics iii ABSTRACT Coherence-Induced Entanglement. (May 2006) Han Xiong, B.S., Peking University; M.S., Chinese Academy...

Xiong, Han

2006-08-16T23:59:59.000Z

342

Breakdown of QCD coherence ?  

E-Print Network (OSTI)

We reconsider the calculation of a non-global QCD observable and find the possible breakdown of QCD coherence. This breakdown arises as a result of wide angle soft gluon emission developing a sensitivity to emission at small angles and it leads to the appearance of super-leading logarithms. We use the `gaps between jets' cross-section as a concrete example and illustrate that the new logarithms are intimately connected with the presence of Coulomb gluon contributions. Numerical estimates of their potential phenomenological significance are presented.

A. Kyrieleis; J. R. Forshaw; M. H. Seymour

2006-12-16T23:59:59.000Z

343

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

344

LDRD final report on continuous wave intersubband terahertz sources.  

SciTech Connect

There is a general lack of compact electromagnetic radiation sources between 1 and 10 terahertz (THz). This a challenging spectral region lying between optical devices at high frequencies and electronic devices at low frequencies. While technologically very underdeveloped the THz region has the promise to be of significant technological importance, yet demonstrating its relevance has proven difficult due to the immaturity of the area. While the last decade has seen much experimental work in ultra-short pulsed terahertz sources, many applications will require continuous wave (cw) sources, which are just beginning to demonstrate adequate performance for application use. In this project, we proposed examination of two potential THz sources based on intersubband semiconductor transitions, which were as yet unproven. In particular we wished to explore quantum cascade lasers based sources and electronic based harmonic generators. Shortly after the beginning of the project, we shifted our emphasis to the quantum cascade lasers due to two events; the publication of the first THz quantum cascade laser by another group thereby proving feasibility, and the temporary shut down of the UC Santa Barbara free-electron lasers which were to be used as the pump source for the harmonic generation. The development efforts focused on two separate cascade laser thrusts. The ultimate goal of the first thrust was for a quantum cascade laser to simultaneously emit two mid-infrared frequencies differing by a few THz and to use these to pump a non-linear optical material to generate THz radiation via parametric interactions in a specifically engineered intersubband transition. While the final goal was not realized by the end of the project, many of the completed steps leading to the goal will be described in the report. The second thrust was to develop direct THz QC lasers operating at terahertz frequencies. This is simpler than a mixing approach, and has now been demonstrated by a few groups with wavelengths spanning 65-150 microns. We developed and refined the MBE growth for THz for both internally and externally designed QC lasers. Processing related issues continued to plague many of our demonstration efforts and will also be addressed in this report.

Samora, Sally; Mangan, Michael A.; Foltynowicz, Robert J.; Young, Erik W.; Fuller, Charles T.; Stephenson, Larry L.; Reno, John Louis; Wanke, Michael Clement; Hudgens, James J.

2005-02-01T23:59:59.000Z

345

On coherence in parametric density estimation  

Science Journals Connector (OSTI)

......1990 research-article Miscellanea On coherence in parametric density estimation J...KullbackLeibler directed divergence has this coherence property whereas the corresponding symmetric...estimation is also discussed. Admissibility|Coherence|Kullback-Leibler divergence|Predictive......

J. AITCHISON

1990-12-01T23:59:59.000Z

346

Coherence lengths and neutron optics  

Science Journals Connector (OSTI)

The dynamical diffraction of divergent beams and its application to neutron interferometry are considered. The coherence properties of thermal neutrons are studied, and it is shown that the extreme anisotropy of dynamically diffracted wave packets should be included in the discussion of coherence lengths. Finally, the mechanism leading to a nondispersive phase shift is investigated.

D. Petrascheck

1987-05-01T23:59:59.000Z

347

Workshop on scientific applications of short wavelength coherent light sources  

SciTech Connect

This report contains paper on the following topics: A 2 to 4nm High Power FEL On the SLAC Linac; Atomic Physics with an X-ray Laser; High Resolution, Three Dimensional Soft X-ray Imaging; The Role of X-ray Induced Damage in Biological Micro-imaging; Prospects for X-ray Microscopy in Biology; Femtosecond Optical Pulses ; Research in Chemical Physics Surface Science, and Materials Science, with a Linear Accelerator Coherent Light Source; Application of 10 GeV Electron Driven X-ray Laser in Gamma-ray Laser Research; Non-Linear Optics, Fluorescence, Spectromicroscopy, Stimulated Desorption: We Need LCLS' Brightness and Time Scale; Application of High Intensity X-rays to Materials Synthesis and Processing; LCLS Optics: Selected Technological Issues and Scientific Opportunities; Possible Applications of an FEL for Materials Studies in the 60 eV to 200 eV Spectral Region.

Spicer, W.; Arthur, J.; Winick, H.

1993-02-01T23:59:59.000Z

348

Workshop on scientific applications of short wavelength coherent light sources  

SciTech Connect

This report contains paper on the following topics: A 2 to 4nm High Power FEL On the SLAC Linac; Atomic Physics with an X-ray Laser; High Resolution, Three Dimensional Soft X-ray Imaging; The Role of X-ray Induced Damage in Biological Micro-imaging; Prospects for X-ray Microscopy in Biology; Femtosecond Optical Pulses?; Research in Chemical Physics Surface Science, and Materials Science, with a Linear Accelerator Coherent Light Source; Application of 10 GeV Electron Driven X-ray Laser in Gamma-ray Laser Research; Non-Linear Optics, Fluorescence, Spectromicroscopy, Stimulated Desorption: We Need LCLS` Brightness and Time Scale; Application of High Intensity X-rays to Materials Synthesis and Processing; LCLS Optics: Selected Technological Issues and Scientific Opportunities; Possible Applications of an FEL for Materials Studies in the 60 eV to 200 eV Spectral Region.

Spicer, W.; Arthur, J.; Winick, H.

1993-02-01T23:59:59.000Z

349

Ultrabroadband coherent supercontinuum frequency comb  

SciTech Connect

We present detailed studies of the coherence properties of an ultrabroadband supercontinuum, enabled by a comprehensive approach involving continuous-wave laser sources to independently probe both the amplitude and phase noise quadratures across the entire spectrum. The continuum coherently spans more than 1.5 octaves, supporting Hz-level comparison of ultrastable lasers at 698 nm and 1.54 {mu}m. We present a complete numerical simulation of the accumulated comb coherence in the limit of many pulses, in contrast to the single-pulse level, with systematic experimental verification. The experiment and numerical simulations reveal the presence of quantum-seeded broadband amplitude noise without phase coherence degradation, including the discovery of a dependence of the supercontinuum coherence on the fiber fractional Raman gain.

Ruehl, Axel; McKay, Hugh; Thomas, Brian; Dong, Liang; Fermann, Martin E.; Hartl, Ingmar [IMRA America Inc., 1044 Woodridge Avenue, Ann Arbor, Michigan 48105 (United States); Martin, Michael J.; Cossel, Kevin C.; Chen Lisheng; Benko, Craig; Ye Jun [JILA, National Institute of Standards and Technology and University of Colorado, Department of Physics, 440 UCB, Boulder, Colorado 80309 (United States); Dudley, John M. [Institute FEMTO-ST, CNRS-University of Franche-Comte UMR 6174, Besancon (France)

2011-07-15T23:59:59.000Z

350

Towards gigawatt terahertz emission by few-cycle laser pulses  

SciTech Connect

It is shown by analysis and simulations that an extremely powerful terahertz (THz) radiation can be produced by a few-cycle laser pulse in a tenuous plasma. The THz amplitude scales linearly with the laser amplitude as well as with the sine of the laser carrier-envelope phase, and in particular, it increases exponentially with the decrease of the laser duration. For example, the THz amplitude increases by near 2 orders of magnitude as the laser duration decreases from one and a half cycles to one cycle; a single-cycle laser of 200 TW can drive the THz radiation of 1 GW with the energy conversion efficiency higher than 10{sup -4}.

Wang Weimin [Beijing National Laboratory of Condensed Matter Physics, Institute of Physics, CAS, Beijing 100190 (China); Graduate School of Engineering, Utsunomiya University, 7-1-2 Yohtoh, Utsunomiya 321-8585 (Japan); Kawata, Shigeo [Graduate School of Engineering, Utsunomiya University, 7-1-2 Yohtoh, Utsunomiya 321-8585 (Japan); Sheng Zhengming; Zhang Jie [Beijing National Laboratory of Condensed Matter Physics, Institute of Physics, CAS, Beijing 100190 (China); Key Laboratory for Laser Plasmas of the Ministry of Education of China and Department of Physics, Shanghai Jiao Tong University, Shanghai 200240 (China); Li Yutong [Beijing National Laboratory of Condensed Matter Physics, Institute of Physics, CAS, Beijing 100190 (China)

2011-07-15T23:59:59.000Z

351

Broadband Excitation and Active Control of Terahertz Plasmons in Graphene  

E-Print Network (OSTI)

A novel broadband technique to effectively launch plasmons along a single graphene layer at terahertz (THz) frequencies is proposed. To this end, the coupling of the electromagnetic wave from a readily available plasmonic waveguide established by a periodically corrugated metallic surface to the graphene sheet is proposed. As will be shown, this technique can significantly surmount the need for efficient excitation of plasmons in graphene. For this purpose, an analytical technique based on transmission line theory is employed to calculate the scattering parameters of the connection of the plasmonic waveguides. In this manner, the gating effects of the graphene waveguide on the input reflection and transmission of the junction are also investigated. For comparison, a full wave numerical simulator is employed.

Khorrami, Mohammad Ali

2014-01-01T23:59:59.000Z

352

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

353

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

354

Coherence in Classical Electromagnetism and Quantum Optics.  

E-Print Network (OSTI)

??This thesis is a study of coherence theory in light in classical electromagnetism and quantum optics. %The coherence is quantified Specifically two quantities are studied:… (more)

Mevik, Hanne-Torill

2009-01-01T23:59:59.000Z

355

Multiphoton Absorption and Coherence  

Science Journals Connector (OSTI)

We study the probability for multiphoton absorption processes induced by both laser and thermal light acting on an atomic system. When the thermal radiation, suitably filtered, has the same frequency spectrum and the same total energy as the laser packet, we find that the ratio between the relative probabilities for s-photon absorption can be expressed by (4?)-12(s-1)s!s12(?c?)s-1, where ? is the time during which the atomic system is illuminated by thermal radiation with coherence time ?c. This shows that multiphoton absorption processes depend on the statistical properties of the incident light, and that the probability induced by the laser packet is certainly greater than that induced by the thermal light if s

S. Carusotto; G. Fornaca; E. Polacco

1968-01-25T23:59:59.000Z

356

Coherence and Partial Coherence in Interacting Electron Systems  

Science Journals Connector (OSTI)

We study coherence of electron transport through interacting quantum dots and discuss the relation of the coherent part to the flux-sensitive conductance for three different types of Aharonov-Bohm interferometers. Contributions to transport in first and second order in the intrinsic linewidth of the dot levels are addressed in detail. We predict an asymmetry of the interference signal around resonance peaks as a consequence of incoherence associated with spin-flip processes. Furthermore, we show by strict calculation that first-order contributions can be partially or even fully coherent. This contrasts with the sequential-tunneling picture which describes first-order transport as a sequence of incoherent processes.

Jürgen König and Yuval Gefen

2001-04-23T23:59:59.000Z

357

Gas breakdown driven by L band short-pulse high-power microwave  

SciTech Connect

High power microwave (HPM) driven gas breakdown is a major factor in limiting the radiation and transmission of HPM. A method that HPM driven gas breakdown could be obtained by changing the aperture of horn antenna is studied in this paper. Changing the effective aperture of horn antenna can adjust the electric field in near field zone, leading to gas breakdown. With this method, measurements of air and SF{sub 6} breakdowns are carried out on a magnetically insulated transmission-line oscillators, which is capable of generating HPM with pulse duration of 30 ns, and frequency of 1.74 GHz. The typical breakdown waveforms of air and SF{sub 6} are presented. Besides, the breakdown field strengths of the two gases are derived at different pressures. It is found that the effects of air and SF{sub 6} breakdown on the transmission of HPM are different: air breakdown mainly shortens the pulse width of HPM while SF{sub 6} breakdown mainly reduces the peak output power of HPM. The electric field threshold of SF{sub 6} is about 2.4 times larger than that of air. These differences suggest that gas properties have a great effect on the transmission characteristic of HPM in gases.

Yang Yiming; Yuan Chengwei; Qian Baoliang [College of Optoelectronic Science and Engineering, National University of Defense Technology, Changsha 410073 (China)

2012-12-15T23:59:59.000Z

358

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

SciTech Connect

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

359

Thermal model design and analysis of the high-power LED automotive headlight cooling device  

Science Journals Connector (OSTI)

Abstract A study of the thermal performance of conventional plate-fin heat sinks and novel cooling device integrated with heat conductive plates (HCPS) for the application in high-power LED headlight was presented. The thermal resistance network model was built to analyze the factors which have impacts on the junction temperature. The analyses were based on the experiment combined with computations using the CFD software FloEFD. The prediction results were validated with the experimental one. Details of the heat transfer performance, particularly the temperature distribution of the LED module and lampshell, as well as the effect of HCPS length on the system thermal resistance and the average heat transfer coefficient were obtained. Since it could make some distance between the heat sink and the lampshell, the average surface convective heat transfer coefficient had been improved and the overall external thermal resistance was reduced effectively. The effects of the simulated ambient temperature, chip package depth, inclination angles and fan rotate speeds on the junction temperature were also examined. Results indicated that the airflow was weakened as the chip package depth increased. In addition, with the presence of the enforced velocity airflow, the junction temperature decreased gradually from 116.61 °C to 78.05 °C.

Xin-Jie Zhao; Yi-Xi Cai; Jing Wang; Xiao-Hua Li; Chun Zhang

2015-01-01T23:59:59.000Z

360

High-Power Electrostatic Discharges in PETN: Threshold and Scaling Experiments  

SciTech Connect

There is a considerable set of data establishing the safety of PETN-based detonators that are insulted by electrostatic discharge (ESD) from a human body. However, the subject of ESD safety has garnered renewed interest because of the sparse data on high-power, low-impedance discharges that result when the source is a metallic object such as a tool. Experiments on as-built components, using pin-to-cap fault circuits through PETN-based detonators, showed significant evidence of a power dependence but with a very broad energy threshold and some uncertainty in the breakdown path. We have performed a series of experiments using a well-defined arc discharge path and a well-characterized source that is capable of independent variation of energy and power. Studies include threshold variation with power, arc length, powder surface area, and surface vs. bulk discharge paths. We find that an energy threshold variation with power does not appear to exist in the tested range of fractions to tens of MW, and that there are many subtleties to proper energy and power bookkeeping. We also present some test results for PBX 9407.

Liou, W; McCarrick, J F; Hodgin, R L; Phillips, D F

2010-03-05T23:59:59.000Z

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.


361

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

SciTech Connect

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

362

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

SciTech Connect

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

363

Use of High?Power Combiners and Fast Directional Switches in ECRH Systems  

Science Journals Connector (OSTI)

The new generation of compact devices for the combination and the fast switching of high?power millimeter?wave beams [1] for Electron Cyclotron Heating (ECH) gives the possibility to switch the power (in tens of microseconds) between two lines (or two ECH launchers even modulating it between them) and combine two gyrotron sources (or in principle even more) in one single transmission line for doubling the transmitted power. This is useful in many respects in order to: 1) ?double the efficiency in modulated EC for neoclassical Tearing Modes (NTM) stabilization 2) avoid to switch?off gyrotrons in conventional (slow) switching 3) electronically control the power sharing between different applications (heating/current?drive or NTM stabilization) 4) upgrade the existing ECH systems to twice the power without adding complete transmission lines and launchers 5) test components at a power doubled with respect to the power capability of the available sources. This opens the way to the development of a more effective “active” real?time control of the ECRH power routing and generally to more flexible and powerful ECH systems. The development of different devices and the advantages for (and in view of) ITER are addressed.

A. Bruschi; W. Kasparek; V. Erckmann; M. Petelin; W. Bin; O. D’Arcangelo; L. Lubyako; V. Muzzini; B. Plaum

2009-01-01T23:59:59.000Z

364

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

SciTech Connect

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

365

Coherence and destruction of coherence in mesoscopic rings  

Science Journals Connector (OSTI)

Recent investigations have shown that an important contribution to the magnetic response of an ensemble of mesoscopic normal metal rings at low temperatures is given by the coherent backscattering familiar fro...

Ulrich Eckern

1991-01-01T23:59:59.000Z

366

Coherence polarization filtering and relation with intrinsic degrees of coherence  

Science Journals Connector (OSTI)

It is demonstrated for stationary fields that when the polarization state of the electric field can be modified arbitrarily the maximal value of the modulus of the degree of coherence...

Réfrégier, Philippe; Roueff, Antoine

2006-01-01T23:59:59.000Z

367

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

368

A Novel High-Power-Factor LED-Lamp Driver Based on a Single-Stage Power Conversion  

Science Journals Connector (OSTI)

This paper proposes a novel single-stage driver for supplying a T8-type light-emitting diode (LED) lamp with high power factor. The presented driver integrates a dual buck-boost converter with coupled inductors and a half-bridge series-resonant converter ... Keywords: converter, driver, light-emitting diode (LED)

Chun An Cheng, En Chih Chang, Ching Shien Tseng, Tsung Yuan Chung

2014-06-01T23:59:59.000Z

369

Analysis and Design of a High Power Density Axial Flux Permanent Magnet Linear Synchronous Machine Used for Stirling System  

Science Journals Connector (OSTI)

a high power density axial flux permanent magnet linear synchronous machine and the stirling system will be introduced. This machine is a tubular axial flux permanent magnet machine. It comprises two parts: stator and mover. With the 2D finite-element ... Keywords: permanent magnet, stirling engine, linear motor

Ping Zheng; Xuhui Gan; Lin Li

2010-09-01T23:59:59.000Z

370

Ultrathin Spinel LiMn2O4 Nanowires as High Power Cathode Materials for Li-Ion Batteries  

E-Print Network (OSTI)

Ultrathin Spinel LiMn2O4 Nanowires as High Power Cathode Materials for Li-Ion Batteries Hyun materials as cathode in lithium ion batteries because of its intrinsic low-cost, environmental friendliness that enhances the contact between active material grains and electrolyte. In particular, LiMn2O4 nanorods

Cui, Yi

371

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

372

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

SciTech Connect

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

373

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

SciTech Connect

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

374

On Coherence Lengths of Wave Packets  

Science Journals Connector (OSTI)

......research-article Articles A60 A64 On Coherence Lengths of Wave Packets Kenzo Ishikawa...University, Sapporo 060-0810, Japan The coherence lengths of one-particle states described...finite spatial size that we call the coherence length. The coherence lengths in the......

Kenzo Ishikawa; Yutaka Tobita

2009-11-01T23:59:59.000Z

375

Durability of Low Platinum Fuel Cells Operating at High Power Density  

SciTech Connect

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

376

Coherence-controlled holographic microscope  

Science Journals Connector (OSTI)

Transmitted-light coherence-controlled holographic microscope (CCHM) based on an off-axis achromatic interferometer allows us to use light sources of arbitrary degree of temporal and...

Kolman, Pavel; Chmelík, Radim

2010-01-01T23:59:59.000Z

377

Laser beat wave excitation of terahertz radiation in a plasma slab  

SciTech Connect

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

378

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

379

Quantum Coherence of Relic Neutrinos  

Science Journals Connector (OSTI)

We argue that in at least a portion of the history of the Universe the relic background neutrinos are spatially extended, coherent superpositions of mass states. We show that an appropriate quantum mechanical treatment affects the neutrino mass values derived from cosmological data. The coherence scale of these neutrino flavor wave packets can be an appreciable fraction of the causal horizon size, raising the possibility of spacetime curvature-induced decoherence.

George M. Fuller and Chad T. Kishimoto

2009-05-22T23:59:59.000Z

380

Terahertz photovoltaic detection of cyclotron resonance in the regime of radiation-induced magnetoresistance oscillations  

Science Journals Connector (OSTI)

We examine and compare the diagonal magnetoresistance, Rxx, and the photovoltage induced by microwave (42?f<300 GHz) and terahertz (f?300 GHz) photoexcitation in the high mobility quasi-two-dimensional GaAs/AlGaAs system. The data demonstrate strong radiation-induced magnetoresistance oscillations in Rxx to 360 GHz. In addition, cyclotron resonance is observed in the photovoltage to 725 GHz. These results show that our high-mobility GaAs/AlGaAs two-dimensional electron system (2DES) specimens remain photoactive in magnetotransport into the terahertz band.

R. G. Mani, A. N. Ramanayaka, Tianyu Ye, M. S. Heimbeck, H. O. Everitt, and W. Wegscheider

2013-06-17T23:59:59.000Z

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381

Composite Cathode for High-Power Density Solid Oxide Fuel Cells  

SciTech Connect

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

382

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

SciTech Connect

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

383

Coherence Holography: A Thought on Synthesis and Analysis of Optical Coherence Fields  

Science Journals Connector (OSTI)

Coherence plays fundamental role in holography and interferometry, and control of coherence is essential in an illumination system for...coherence holography..., which was developed recently for synthesis and ana...

Mitsuo Takeda; Wei Wang; Dinesh N. Naik

2009-01-01T23:59:59.000Z

384

Aqueous blackbody calibration source for millimeter-wave/terahertz metrology  

SciTech Connect

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

385

Tuning the response of terahertz metamaterial at low temperatures  

SciTech Connect

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

386

Coherent quasiparticle approximation cQPA and nonlocal coherence  

E-Print Network (OSTI)

We show that the dynamical Wigner functions for noninteracting fermions and bosons can have complex singularity structures with a number of new solutions accompanying the usual mass-shell dispersion relations. These new shell solutions are shown to encode the information of the quantum coherence between particles and antiparticles, left and right moving chiral states and/or between different flavour states. Analogously to the usual derivation of the Boltzmann equation, we impose this extended phase space structure on the full interacting theory. This extension of the quasiparticle approximation gives rise to a self-consistent equation of motion for a density matrix that combines the quantum mechanical coherence evolution with a well defined collision integral giving rise to decoherence. Several applications of the method are given, for example to the coherent particle production, electroweak baryogenesis and study of decoherence and thermalization.

Matti Herranen; Kimmo Kainulainen; Pyry M. Rahkila

2009-12-14T23:59:59.000Z

387

Coherence Holography and Spatial Frequency Comb for 3-D Coherence Imaging  

Science Journals Connector (OSTI)

The principle and the applications of a recently proposed unconventional holography technique, called coherence holography, and a related technique for dispersion-free 3-D coherence...

Takeda, Mitsuo; Wang, Wei; Duan, Zhihui; Miyamoto, Yoko; Rosen, Joseph

388

Coherence and polarization properties of a radially polarized beam with variable spatial coherence  

Science Journals Connector (OSTI)

In a recent publication [Appl. Phys. Lett, 100, 051108 (2012)], a radially polarized (RP) beam with variable spatial coherence (i.e., partially coherent RP beam) was generated...

Wu, Gaofeng; Wang, Fei; Cai, Yangjian

2012-01-01T23:59:59.000Z

389

Coherence-Controlled Holographic Microscopy for Coherence-Gated Quantitative Phase Imaging  

Science Journals Connector (OSTI)

We show that the use of incoherent illumination in coherence-controlled holographic microscopy (CCHM) enables coherence-gated quantitative phase imaging of objects through turbid...

Slaby, Tomas; Kolman, Pavel; Dostal, Zbynek; Antos, Martin; Lostak, Martin; Krizova, Aneta; Collakova, Jana; Kollarova, Vera; Slaba, Michala; Vesely, Pavel; Chmelik, Radim

390

Long-term research in Japan: amorphous metals, metal oxide varistors, high-power semiconductors and superconducting generators  

SciTech Connect

The review revealed that significant activity is under way in the research of amorphous metals, but that little fundamental work is being pursued on metal oxide varistors and high-power semiconductors. Also, the investigation of long-term research program plans for superconducting generators reveals that activity is at a low level, pending the recommendations of a study currently being conducted through Japan's Central Electric Power Council.

Hane, G.J.; Yorozu, M.; Sogabe, T.; Suzuki, S.

1985-04-01T23:59:59.000Z

391

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.

392

THE MERIT HIGH-POWER TARGET EXPERIMENT AT THE CERN PS K.T. McDonald,  

E-Print Network (OSTI)

37831, U.S.A. P.H. Titus, Princeton Plasma Physics Laboratory, Princeton, NJ 08543, U.S.A. JTHE MERIT HIGH-POWER TARGET EXPERIMENT AT THE CERN PS K.T. McDonald, Princeton University, Princeton, NJ 08544, U.S.A. H.G. Kirk, H. Park, T. Tsang, BNL, Upton, NY 11973, U.S.A. I. Efthymiopoulos, A

McDonald, Kirk

393

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

SciTech Connect

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

394

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 investigate the relative entropic measure of coherence. Based on its analytical expression, we give an operational interpretation of it with respect to the concept of quantum channel. On this basis, we derive the relation about the coherence and the coherent information in any quantum state. From the point of view of quantum measurement, we furthermore give three trade-offs among the coherence, discord-like and deficit-like quantum correlation quantities for any bipartite quantum state. As an application, we discuss the coherent property of the amplitude damping channel.

Zhengjun Xi; Yongming Li; Heng Fan

2014-08-14T23:59:59.000Z

395

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

NLE Websites -- All DOE Office Websites (Extended Search)

development of low cost LiFePO4-based high power lithium-ion batteries development of low cost LiFePO4-based high power lithium-ion batteries Title The development of low cost LiFePO4-based high power lithium-ion batteries Publication Type Journal Article Year of Publication 2005 Authors Striebel, Kathryn A., Joongpyo Shim, Azucena Sierra, Hui Yang, Xiangyun Song, Robert Kostecki, and Kathryn N. McCarthy Journal Journal of Power Sources Volume 146 Pagination 33-38 Keywords libob, lifepo4, lithium-ion, post-test, raman spectroscopy Abstract Pouch type LiFePO4-natural graphite lithium-ion cells were cycled at constant current with periodic pulse-power testing in several different configurations. Components were analyzed after cycling with electrochemical, Raman and TEM techniques to determine capacity fade mechanisms. The cells with carbon-coated current collectors in the cathode and LiBOB-salt electrolyte showed the best performance stability. In many cases, iron species were detected on the anodes removed from cells with both TEM and Raman spectroscopy. The LiFePO4 electrodes showed unchanged capacity suggesting that the iron is migrating in small quantities and is acting as a catalyst to destabilize the anode SEI in these cells.

396

Terahertz imaging of subjects with concealed weapons Jason C. Dickinson*a  

E-Print Network (OSTI)

Terahertz imaging of subjects with concealed weapons Jason C. Dickinson*a , Thomas M. Goyettea for concealed weapons detection, the Submillimeter-Wave Technology Laboratory (STL) at the University-the-fly processing. Imagery at 1.56THz of human subjects with concealed weapons are presented and discussed

Massachusetts at Lowell, University of

397

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

398

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.

399

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

400

Terahertz Time Domain Spectroscopy of Phonon-Depopulation Based Quantum Cascade Lasers  

SciTech Connect

A 3.1 THz phonon depopulation-based quantum-cascade-laser is investigated using terahertz time domain spectroscopy. A gain of 25 cm{sup -1} and absorption features due to the lower laser level being populated from a parasitic electronic channel are highlighted.

Rungsawang, R.; Dhillon, S. S.; Jukam, N.; Oustinov, D.; Madeo, J.; Tignon, J. [Laboratoire Pierre Aigrain, Ecole Normale Superieure, UMR8551 CNRS, UPMC Univ. Paris 6, F-75005 Paris (France); Colombelli, R. [Institut d'Electronique Fondamentale, Universite Paris Sud, UMR8622 CNRS, 91405 Orsay (France); Dean, P.; Salih, M.; Khanna, S. P.; Linfield, E.; Davies, A. G. [School of Electronic and Electrical Engineering, University of Leeds, Leeds, LS2 9JT (United Kingdom)

2011-12-23T23:59:59.000Z

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

High-contrast terahertz modulator based on extraordinary transmission through a ring  

E-Print Network (OSTI)

). 6. H.-T. Chen, W. J. Padilla, J. M. O. Zide, A. C. Gossard, A. J. Taylor, and R. D. Averitt, "Active. Azad, R. D. Averitt, A. C. Gossard, S. A. Trugman, J. F. O'Hara, and A. J. Taylor, "Electronic control-pixel terahertz imaging system based on compressed sensing," Appl. Phys. Lett. 93(12), 121105 (2008). 2. T. Kleine

Mellor-Crummey, John

402

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

403

Creating coherent animations from video  

Science Journals Connector (OSTI)

In this paper, different techniques for the creation of time coherent figurative animations from a video input are presented. The animations are generated using an analysis-synthesis approach. Information of the scene is extracted using only a 2D RGB image. No markers or depth planes are needed. After the analysis, the image is drawn again using the extracted information. To guarantee temporal coherence when redrawing the image, different alternatives have been explored: matching and interpolation on the parameters domain and gradient descent parameter update. All methods and variations are described and illustrated with images.

Javier Villegas; George Legrady

2014-01-01T23:59:59.000Z

404

Partial coherence with twin photons  

Science Journals Connector (OSTI)

An approach for calculating fourth-order coherence functions between fields produced in the parametric down-conversion process is proposed. It takes into account the transverse correlations between twin photons and is used to calculate the visibility of the interference patterns obtained in double-slit experiments with coincidence detection. The finite dimension of the light source and detectors are shown to be responsible for a kind of partial coherence which affects the visibility of the fringes. The results explain known features and predict other ones.

P. H. Souto Ribeiro

1997-11-01T23:59:59.000Z

405

Coherence Properties and Photon Correlation  

Science Journals Connector (OSTI)

An intensity-correlation experiment is proposed to test the second-order coherence of laser light from a cw-operated laser based on the Glauber formalism. The calculation utilizes the known form of the density matrix for radiation from a randomly excited source such as a discharge tube which is equivalent to filtered black-body radiation, and represents the laser radiation field by a coherent state. The intensity correlation calculated exhibits the standard Hanbury Brown-Twiss term and an extra term due to intensity interference between the Fourier components of the thermal field and the laser mode.

Hans Morawitz

1965-08-16T23:59:59.000Z

406

Coherence in Spontaneous Radiation Processes  

Science Journals Connector (OSTI)

By considering a radiating gas as a single quantum-mechanical system, energy levels corresponding to certain correlations between individual molecules are described. Spontaneous emission of radiation in a transition between two such levels leads to the emission of coherent radiation. The discussion is limited first to a gas of dimension small compared with a wavelength. Spontaneous radiation rates and natural line breadths are calculated. For a gas of large extent the effect of photon recoil momentum on coherence is calculated. The effect of a radiation pulse in exciting "super-radiant" states is discussed. The angular correlation between successive photons spontaneously emitted by a gas initially in thermal equilibrium is calculated.

R. H. Dicke

1954-01-01T23:59:59.000Z

407

Coherence length of neutron superfluids  

Science Journals Connector (OSTI)

The coherence length of superfluid neutron matter is calculated from the microscopic BCS wave function of a Cooper pair in momentum space making use of recent nucleon-nucleon potential models and including polarization (RPA) effects. We find as our main result that the coherence length is proportional to the Fermi momentum to pairing gap ratio, in good agreement with simple estimates used in the literature, with a nearly interaction independent constant of proportionality. Our calculations can be applied to the problem of inhomogeneous superfluidity of hadronic matter in the crust of a neutron star.

F. V. De Blasio; M. Hjorth-Jensen; Ø. Elgarøy; L. Engvik; G. Lazzari; M. Baldo; H.-J. Schulze

1997-10-01T23:59:59.000Z

408

Terahertz time-domain imaging of hidden defects in wooden artworks: application to a Russian icon painting  

Science Journals Connector (OSTI)

We use terahertz time-domain imaging and time-of-flight tomography to examine subsurface defects in an early-19th-century Russian icon painting. In the transmission geometry, we...

Skryl, Anton S; Jackson, J Bianca; Bakunov, Michael I; Menu, Michel; Mourou, Gerard A

2014-01-01T23:59:59.000Z

409

Study of methods for lowering the lasing frequency of a terahertz quantum-cascade laser based on two quantum wells  

Science Journals Connector (OSTI)

Two mechanisms for achieving lower terahertz-range frequencies in quantum-cascade structures with two quantum wells based on GaAs/AlGaAs compounds are ... mechanism is based on the introduction of composite quantum

D. V. Ushakov; Yu. G. Sadofyev; N. Samal

2012-11-01T23:59:59.000Z

410

Energy-Scalable THz-Wave Parametric Oscillator and Its Application to Scanning-Beam Terahertz-Wave Reflection Imaging  

Science Journals Connector (OSTI)

We describe an energy-scalable surface-emitted terahertz-wave parametric oscillator (TPO) with output energy that was six times higher than that of the conventional TPO....

Ikari, Tomofumi; Minamide, Hiroaki; Ito, Hiromasa

411

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.

412

Phenotyping transgenic embryonic murine hearts using optical coherence tomography  

E-Print Network (OSTI)

Phenotyping transgenic embryonic murine hearts using optical coherence tomography Michael W optical coherence tomography (OCT) to characterize the morphological phenotype of embryonic murine hearts the etiology of heart defects. Optical coherence tomography (OCT)6,7 measures coherently gated backreflected

413

Heralded single-photon partial coherence  

Science Journals Connector (OSTI)

We study transverse spatial coherence of approximately localized single-photon states. We demonstrate nonlocal control over single-photon spatial coherence via projective measurements of an entangled twin and provide a theoretical interpretation from quantum coherence theory. Our results show that the spatial coherence of a single-photon state behaves similarly to that of a classical optical field, although the coincidence measurement adds a degree of freedom.

P. Ben Dixon; Gregory Howland; Mehul Malik; David J. Starling; R. W. Boyd; John C. Howell

2010-08-02T23:59:59.000Z

414

Heralded single-photon partial coherence  

SciTech Connect

We study transverse spatial coherence of approximately localized single-photon states. We demonstrate nonlocal control over single-photon spatial coherence via projective measurements of an entangled twin and provide a theoretical interpretation from quantum coherence theory. Our results show that the spatial coherence of a single-photon state behaves similarly to that of a classical optical field, although the coincidence measurement adds a degree of freedom.

Dixon, P. Ben; Howland, Gregory; Starling, David J.; Howell, John C. [Department of Physics and Astronomy, University of Rochester, Rochester, New York 14627 (United States); Malik, Mehul [Institute of Optics, University of Rochester, Rochester, New York 14627 (United States); Boyd, R. W. [Department of Physics and Astronomy, University of Rochester, Rochester, New York 14627 (United States); Institute of Optics, University of Rochester, Rochester, New York 14627 (United States)

2010-08-15T23:59:59.000Z

415

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

416

Scalar Diffraction in Terms of Coherence  

Science Journals Connector (OSTI)

...research-article Scalar Diffraction in Terms of Coherence W. H. Steel In scalar diffraction theory...correlation function, here called the 'coherence', rather than in quantities such as...diffraction is developed here based on the coherence between radiation at pairs of points...

1959-01-01T23:59:59.000Z

417

Coherence principles in dose-finding studies  

Science Journals Connector (OSTI)

......Trust December 2005 Article Articles Coherence principles in dose-finding studies...Revised April 2005. This paper studies the coherence conditions of dose-finding methods...toxic outcome has just been seen. The coherence conditions, motivated by ethical concerns......

Ying Kuen Cheung

2005-12-01T23:59:59.000Z

418

Coherence Frame, Entanglement Conservation, and Einselection  

E-Print Network (OSTI)

In this paper, the theory of coherence frame is developed. Two kinds of coherence frame are classified. Under coherence frame, the entanglement is conserved in the entanglement swapping process, without entanglement sudden death and birth. The einselection method for the preferred basis problem in the entangle process is shown as incomplete.

Dong-Sheng Wang

2011-04-29T23:59:59.000Z

419

Coherence Properties of Optical Fields  

Science Journals Connector (OSTI)

This article presents a review of coherence properties of electromagnetic fields and their measurements, with special emphasis on the optical region of the spectrum. Analyses based on both the classical and quantum theories are described. After a brief historical introduction, the elementary concepts which are frequently employed in the discussion of interference phenomena are summarized. The measure of second-order coherence is then introduced in connection with the analysis of a simple interference experiment and some of the more important second-order coherence effects are studied. Their uses in stellar interferometry and interference spectroscopy are described. Analysis of partial polarization from the standpoint of correlation theory is also outlined. The general statistical description of the field is discussed in some detail. The recently discovered universal "diagonal" representation of the density operator for free fields is also considered and it is shown how, with the help of the associated generalized phase-space distribution function, the quantum-mechanical correlation functions may be expressed in the same form as the classical ones. The sections which follow deal with the statistical properties of thermal and nonthermal light, and with the temporal and spatial coherence of blackbody radiation. Later sections, dealing with fourth- and higher-order coherence effects include a discussion of the photoelectric detection process. Among the fourth-order effects described in detail are bunching phenomena, the Hanbury Brown-Twiss effect and its application to astronomy. The article concludes with a discussion of various transient superposition effects, such as light beats and interference fringes produced by independent light beams.

L. MANDEL and E. WOLF

1965-04-01T23:59:59.000Z

420

Coherence vortices in one spatial dimension  

SciTech Connect

Coherence vortices are screw-type topological defects in the phase of Glauber's two-point degree of quantum coherence, associated with pairs of spatial points at which an ensemble-averaged stochastic quantum field is uncorrelated. Coherence vortices may be present in systems whose dimensionality is too low to support spatial vortices. We exhibit lattices of such quantum-coherence phase defects for a one-dimensional model quantum system. We discuss the physical meaning of coherence vortices and propose how they may be realized experimentally.

Simula, Tapio P.; Paganin, David M. [School of Physics, Monash University, Victoria 3800 (Australia)

2011-11-15T23:59:59.000Z

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.


421

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

SciTech Connect

The cycling performance of low-cost LiFePO4-based high-power lithium-ion cells was investigated and the components were analyzed after cycling to determine capacity fade mechanisms. Pouch type LiFePO4/natural graphite cells were assembled and evaluated by constant C/2 cycling, pulse-power and impedance measurements. From post-test electrochemical analysis after cycling, active materials, LiFePO4 and natural graphite, showed no degradation structurally or electrochemically. The main reasons for the capacity fade of cell were lithium inventory loss by side reaction and possible lithium deposition on the anode.

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

2003-11-25T23:59:59.000Z

422

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

SciTech Connect

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

423

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

424

Quantum coherence in two dimensions  

Science Journals Connector (OSTI)

The formation and evaporation of two-dimensional black holes are discussed. It is shown that if the radiation in minimal scalars has positive energy, there must be a global event horizon or a naked singularity. The former would imply loss of quantum coherence while the latter would lead to an even worse breakdown of predictability. CPT invariance would suggest that there ought to be past horizons as well. A way in which this could happen with wormholes is described.

S. W. Hawking and J. D. Hayward

1994-05-15T23:59:59.000Z

425

Coherence effects in neutrino oscillations  

Science Journals Connector (OSTI)

We study the effect of coherent and incoherent broadening on neutrino oscillations both in vacuum and in the presence of matter (the MSW effect). We show under very general assumptions that it is not possible to distinguish experimentally neutrinos produced in some region of space as wave packets from those produced in the same region of space as plane waves with the same energy distribution. © 1995 The American Physical Society.

Ken Kiers; Shmuel Nussinov; Nathan Weiss

1996-01-01T23:59:59.000Z

426

Wafer-scale surface roughening for enhanced light extraction of high power AlGaInP-based light-emitting diodes  

Science Journals Connector (OSTI)

A new approach to surface roughening was established and optimized in this paper for enhancing the light extraction of high power AlGaInP-based LEDs, by combining ultraviolet (UV)...

Park, Hyeong-Ho; Zhang, Xin; Cho, Yunae; Kim, Dong-Wook; Kim, Joondong; Lee, Keun Woo; Choi, Jehyuk; Lee, Hee Kwan; Jung, Sang Hyun; Her, Eun Jin; Kim, Chang Hwan; Moon, A-Young; Shin, Chan-Soo; Shin, Hyun-Beom; Sung, Ho Kun; Park, Kyung Ho; Park, Hyung-Ho; Kim, Hi-Jung; Kang, Ho Kwan

2014-01-01T23:59:59.000Z

427

Analysis of spectra of acoustic signals generated by high-power pulsed laser radiation propagating in the atmosphere. I. Spectra of local plasma formations  

Science Journals Connector (OSTI)

Results of theoretical and experimental investigations into the spectra of acoustic signals generated by high-power pulsed laser radiation propagating in the atmosphere in the breakdown mode are given in ... of a...

S. V. Shamanaev; L. G. Shamanaeva

2005-11-01T23:59:59.000Z

428

Ultrafast terahertz-induced response of GeSbTe phase-change materials Michael J. Shu,1,2,a)  

E-Print Network (OSTI)

Ultrafast terahertz-induced response of GeSbTe phase-change materials Michael J. Shu,1,2,a) Peter-optically, pumping with single-cycle terahertz pulses as a means of biasing phase-change materials on a sub of these materials is important for predicting the field-driven heating and phase-change behavior. However

429

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

430

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

431

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

SciTech Connect

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

432

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

SciTech Connect

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

433

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

434

OPTICS LETTERS / Vol. 30, No. 22 / November 15, 2005, pp 3030-3032 Evidence of thermal effects in high power Er3+  

E-Print Network (OSTI)

power 1.55µm double cladding Erbium-Ytterbium fiber laser. At strong pumping rates, 1µm lasing can start be obtained using double-clad doped fiber pumped with broad area high power pump laser diodes. Double-clad in high power Er3+ -Yb3+ fiber laser G. Canat, J.-C. Mollier DOTA, ONERA, Chemin de la Hunière, 91761

Boyer, Edmond

435

Analysis and design of terahertz antennas based on plasmonic resonant graphene sheets  

SciTech Connect

Resonant graphene antennas used as true interfaces between terahertz (THz) space waves and a source/detector are presented. It is shown that in addition to the high miniaturization related to the plasmonic nature of the resonance, graphene-based THz antenna favorably compare with typical metal implementations in terms of return loss and radiation efficiency. Graphene antennas will contribute to the development of miniature, efficient, and potentially transparent all-graphene THz transceivers for emerging communication and sensing application.

Tamagnone, M. [Adaptive MicroNano Wave Systems, LEMA/Nanolab, Ecole Polytechnique Federale de Lausanne (EPFL), 1015 Lausanne (Switzerland); Laboratory of Electromagnetics and Acoustics (LEMA), Ecole Polytechnique Federale de Lausanne (EPFL), 1015 Lausanne (Switzerland); Gomez-Diaz, J. S.; Perruisseau-Carrier, J. [Adaptive MicroNano Wave Systems, LEMA/Nanolab, Ecole Polytechnique Federale de Lausanne (EPFL), 1015 Lausanne (Switzerland); Mosig, J. R. [Laboratory of Electromagnetics and Acoustics (LEMA), Ecole Polytechnique Federale de Lausanne (EPFL), 1015 Lausanne (Switzerland)

2012-12-01T23:59:59.000Z

436

Mode-locked terahertz quantum cascade laser by direct phase synchronization  

SciTech Connect

Mode-locking of a terahertz quantum cascade laser is achieved using multimode injection seeding. Contrary to standard methods that rely on gain modulation, here a fixed phase relationship is directly imprinted to the laser modes. In this work, we demonstrate the generation of 9 ps phase mode-locked pulses around 2.75 THz. A direct measurement of the emitted field phase shows that it results from the phase of the initial injection.

Maussang, K.; Maysonnave, J.; Jukam, N.; Freeman, J. R.; Cavalié, P.; Dhillon, S. S.; Tignon, J. [Laboratoire Pierre Aigrain, Ecole Normale Supérieure, CNRS (UMR 8551), Université P. et M. Curie, Université D. Diderot, 75005 Paris (France); Khanna, S. P.; Linfield, E. H.; Davies, A. G. [School of Electronic and Electrical Engineering, University of Leeds, Leeds LS9 2JT (United Kingdom); Beere, H. E.; Ritchie, D. A. [University of Cambridge, Cavendish Lab, Cambridge CB3 0HE (United Kingdom)

2013-12-04T23:59:59.000Z

437

Mechanism of terahertz photoconductivity in semimetallic HgTe/CdHgTe quantum wells  

SciTech Connect

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

438

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

439

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

440

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,
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

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

442

Low-coherence doppler lidar with multiple time coherence of reference and probe waves  

Science Journals Connector (OSTI)

The notion of multiple time coherence of optical beams is introduced and mathematically ... pulses (MFPs), which exhibit multiple time coherence, and the possibility of their application for ... is based on nanos...

G. G. Matvienko; S. N. Polyakov; V. K. Oshlakov

2007-11-01T23:59:59.000Z

443

Low-cost, high-power mechanical impact transducers for sonar and acoustic through-wall surveillance applications  

E-Print Network (OSTI)

A new concept is presented for mechanical acoustic transmitters and matched resonant receivers. The lightweight, compact, and low-cost transmitters produce high-power acoustic pulses at one or more discrete frequencies with very little input power. The transducer systems are well suited for coupling acoustic pulse energy into dense media, such as walls and water. Applications of the impact transducers are discussed, including detection and tracking of humans through walls and long-duration underwater surveillance by a low-cost network of autonomous, self-recharging, battery-operated sonobuoys. A conceptual design of a sonobuoy surveillance network for harbors and littoral waters is presented. An impact-transmitter and matched-receiver system that detected human motion through thick walls with only rudimentary signal processing is described, and results are presented. Signal processing methods for increasing the signal-to-noise ratio by several tens of dB are discussed.

Felber, Franklin

2014-01-01T23:59:59.000Z

444

Numerical investigation of the physical model of a high-power electromagnetic wave in a magnetically insulated transmission line  

SciTech Connect

An efficient numerical code for simulating the propagation of a high-power electromagnetic pulse in a vacuum transmission line is required to study the physical phenomena occurring in such a line, to analyze the operation of present-day megavolt generators at an {approx}10-TW power level, and to design such new devices. The main physical theoretical principles are presented, and the stability of flows in the near-threshold region at the boundary of the regime of magnetic self-insulation is investigated based on one-dimensional telegraph equations with electron losses. Numerical (difference) methods-specifically, a method of characteristics and a finite-difference scheme-are described and their properties and effectiveness are compared by analyzing the high-frequency modes.

Samokhin, A. A. [Troitsk Institute for Innovation and Fusion Research (Russian Federation)

2010-02-15T23:59:59.000Z

445

Ppb-level QEPAS NO2 sensor by use of electrical modulation cancellation method with a high power blue LED  

Science Journals Connector (OSTI)

Abstract A novel electrical modulation cancellation method (E-MOCAM) is proposed to suppress the background noise in the case of the excitation light source with a poor beam quality. For its practical implementation, an E-MOCAM based on-beam QEPAS NO2 sensor by use of a commercial high-power wide-stripe LED is developed. The E-MOCAM ultimately suppressed the background noise caused by the stray light by three orders of magnitude. A 1? detection limit of 1.3 ppb (part per billion by volume) was achieved at 1 s integration time in this experiment, which corresponds to a normalized noise equivalent absorption coefficient (NNEA) 4.2 × 10?9 W cm?1 Hz?1/2. A 9 h continuous on-line monitoring of ambient atmospheric NO2 was carried out on the campus of Shanxi University.

Huadan Zheng; Lei Dong; Xukun Yin; Xiaoli Liu; Hongpeng Wu; Lei Zhang; Weiguang Ma; Wangbao Yin; Suotang Jia

2015-01-01T23:59:59.000Z

446

Plasma diagnostics of low pressure high power impulse magnetron sputtering assisted by electron cyclotron wave resonance plasma  

SciTech Connect

This paper reports on an investigation of the hybrid pulsed sputtering source based on the combination of electron cyclotron wave resonance (ECWR) inductively coupled plasma and high power impulse magnetron sputtering (HiPIMS) of a Ti target. The plasma source, operated in an Ar atmosphere at a very low pressure of 0.03 Pa, provides plasma where the major fraction of sputtered particles is ionized. It was found that ECWR assistance increases the electron temperature during the HiPIMS pulse. The discharge current and electron density can achieve their stable maximum 10 {mu}s after the onset of the HiPIMS pulse. Further, a high concentration of double charged Ti{sup ++} with energies of up to 160 eV was detected. All of these facts were verified experimentally by time-resolved emission spectroscopy, retarding field analyzer measurement, Langmuir probe, and energy-resolved mass spectrometry.

Stranak, Vitezslav [Ernst-Moritz-Arndt-Universitaet Greifswald, Institut fuer Physik, Felix-Hausdorff-Str. 6, 17489 Greifswald (Germany); University of South Bohemia, Institute of Physics and Biophysics, Branisovska 31, 370 05 Ceske Budejovice (Czech Republic); Herrendorf, Ann-Pierra; Drache, Steffen; Bogdanowicz, Robert; Hippler, Rainer [Ernst-Moritz-Arndt-Universitaet Greifswald, Institut fuer Physik, Felix-Hausdorff-Str. 6, 17489 Greifswald (Germany); Cada, Martin; Hubicka, Zdenek [Institute of Physics v. v. i., Academy of Science of the Czech Republic, Na Slovance 2, 182 21 Prague (Czech Republic); Tichy, Milan [Charles University in Prague, Faculty of Mathematics and Physics, V Holesovickach 2, 180 00 Prague (Czech Republic)

2012-11-01T23:59:59.000Z

447

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

SciTech Connect

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

448

Laser-induced "two-atom" coherence  

Science Journals Connector (OSTI)

Our analysis shows that if an electromagnetic field excites a coherent superposition of states of two different types of atoms, then the results of a collision of those two atoms can be quite different from the usual dephasing that a coherently excited atom suffers upon collision with another atom. We present the concept of "two-atom" coherence as one feature of this interaction where the field of a given wavelength may interact with the system coherently over a wide range of internuclear distances.

Munir H. Nayfeh and G. B. Hillard

1984-04-01T23:59:59.000Z

449

Coherent Control of Quantum Matter  

SciTech Connect

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

450

coherence  

Science Journals Connector (OSTI)

1. Pertaining to a correlation between the phase points of two waves, such as lightwaves or radio waves, at the same instant or at the same point in space. 2. Pertaining to a correlation between the ...

2001-01-01T23:59:59.000Z

451

Coherence and Conservatism in the Dynamics of Belief II: Iterated Belief Change without Dispositional Coherence  

Science Journals Connector (OSTI)

......University Press 2003 Original Article Coherence and Conservatism in the Dynamics of Belief...Iterated Belief Change without Dispositional Coherence Hans Rott 1 1 Department of Philosophy...based on the conclusions of Rott, Coherence and Conservatism in the Dynamics of Belief......

Hans Rott

2003-02-01T23:59:59.000Z

452

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

SciTech Connect

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

453

Coherence and Flexibility in Dialogue Games for Argumentation  

Science Journals Connector (OSTI)

......2005 Original Article Original Articles Coherence and Flexibility in Dialogue Games for...particular, it allows for varying degrees of coherence and flexibility when it comes to maintaining...dialogue games, defeasible reasoning| Coherence and Flexibility in Dialogue Games for......

Henry Prakken

2005-12-01T23:59:59.000Z

454

Spin coherence transfer in chemical transformations monitored NMR  

E-Print Network (OSTI)

the transfer of spin coherence in non-equilibrium chemicalK. L. Pierce, A. Pines ? Spin coherence transfer in chemical10.1002/anie.200123456 Spin Coherence Transfer in Chemical

Anwar, Sabieh M.; Hilty, Christian; Chu, Chester; Bouchard, Louis-S.; Pierce, Kimberly L.; Pines, Alexander

2006-01-01T23:59:59.000Z

455

Coherence and Completeness of Population-based Family Cancer Reports  

Science Journals Connector (OSTI)

...research-article Research Articles Coherence and Completeness of Population-based...telephone survey in Connecticut examined coherence and completeness of reports from 1...household survey. This study describes the coherence and completeness of such reports in a...

Louise Wideroff; Anne O. Garceau; Mark H. Greene; Marsha Dunn; Timothy McNeel; Phuong Mai; Gordon Willis; Lou Gonsalves; Michael Martin; Barry I. Graubard

2010-03-01T23:59:59.000Z

456

COMMON KNOWLEDGE, COHERENT UNCERTAINTIES AND CONSENSUS  

E-Print Network (OSTI)

COMMON KNOWLEDGE, COHERENT UNCERTAINTIES AND CONSENSUS by Yakov Ben-Haim TECHNICAL REPORT ETR-2001 of Mechanical Engineering #12;Working Paper Common Knowledge, Coherent Uncertainties and Consensus Yakov Ben- and knowledge-functions, common knowledge and consensus. Our main results are that knowledge is constricted

Rimon, Elon

457

Time-optimal transfer of coherence  

Science Journals Connector (OSTI)

We provide exact analytical solutions for the problem of time-optimal transfer of coherence from one spin-polarization to a threefold coherence in a trilinear Ising chain with a fixed energy available and subject to local controls with a non-negligible time cost. The time of transfer is optimal and consistent with a previous numerical result obtained assuming instantaneous local controls.

Alberto Carlini and Tatsuhiko Koike

2012-11-26T23:59:59.000Z

458

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

SciTech Connect

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

459

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

460

Science and Instrumentation for the Linac Coherent Light Source...  

NLE Websites -- All DOE Office Websites (Extended Search)

of the proposed Linac Coherent Light Source (LCLS): subpicosecond time-structure, coherence and unprecedented high averagepeak brightness in the angstrom spectral region. The...

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

Coherence length tunable semiconductor laser with optical feedback  

Science Journals Connector (OSTI)

We report the experimental results to continuously tune the coherence length of a semiconductor laser using an optical feedback scheme. The coherence length can be controlled by...

Wang, Yuncai; Kong, Lingqin; Wang, Anbang; Fan, Linlin

2009-01-01T23:59:59.000Z

462

Coherence-Preserving Quantum Bits  

Science Journals Connector (OSTI)

Real quantum systems couple to their environment and lose their intrinsic quantum nature through the process known as decoherence. Here we present a method for minimizing decoherence by making it energetically unfavorable. We present a Hamiltonian made up solely of two-body interactions between four two-level systems (qubits) which has a 2-fold degenerate ground state. This degenerate ground state has the property that any decoherence process acting on an individual physical qubit must supply energy from the bath to the system. Quantum information can be encoded into the degeneracy of the ground state and such coherence-preserving qubits will then be robust to local decoherence at low bath temperatures. We show how this quantum information can be universally manipulated and indicate how this approach may be applied to a quantum dot quantum computer.

Dave Bacon; Kenneth R. Brown; K. Birgitta Whaley

2001-11-26T23:59:59.000Z

463

Probing the plasma near high power wave launchers in fusion devices for static and dynamic electric fields  

SciTech Connect

An exploratory study was carried out in the long-pulse tokamak Tore Supra, to determine if electric fields in the plasma around high-power, RF wave launchers could be measured with non-intrusive, passive, optical emission spectroscopy. The focus was in particular on the use of the external electric field Stark effect. The feasibility was found to be strongly dependent on the spatial extent of the electric fields and overlap between regions of strong (> 1 kV/cm) electric fields and regions of plasma particle recycling and plasma-induced, spectral line emission. Most amenable to the measurement was the RF electric field in edge plasma, in front of a lower hybrid heating and current drive launcher. Electric field strengths and direction, derived from fitting the acquired spectra to a model including time-dependent Stark effect and the tokamak-range magnetic field Zeeman-effect, were found to be in good agreement with full-wave modeling of the observed launcher.

Klepper, C Christopher [ORNL; Martin, Elijah H [ORNL; Isler, Ralph C [ORNL; Colas, L. [French Atomic Energy Commission (CEA), Cadarache, St. Paul lez Durance; Goniche, M. [French Atomic Energy Commission (CEA), Cadarache, St. Paul lez Durance; Hillairet, J. [French Atomic Energy Commission (CEA), Institute for Magnetic Fusion Research (IRFM); Panayotis, Stephanie [French Atomic Energy Commission (CEA), Institute for Magnetic Fusion Research (IRFM); Jacquot, Jonathan [French Atomic Energy Commission (CEA), Institute for Magnetic Fusion Research (IRFM); Lotte, Ph. [French Atomic Energy Commission (CEA), Cadarache, St. Paul lez Durance; Colledani, G. [French Atomic Energy Commission (CEA), Institute for Magnetic Fusion Research (IRFM); Biewer, Theodore M [ORNL; Caughman, J. B. O. [Oak Ridge National Laboratory (ORNL); Ekedahl, A. [French Atomic Energy Commission (CEA), Institute for Magnetic Fusion Research (IRFM); Green, David L [ORNL; Harris, Jeffrey H [ORNL; Hillis, Donald Lee [ORNL; Shannon, Prof. Steven [North Carolina State University; Litaudon, X [French Atomic Energy Commission (CEA)

2014-01-01T23:59:59.000Z

464

Study on thermal performance of high power LED employing aluminum filled epoxy composite as thermal interface material  

Science Journals Connector (OSTI)

Abstract This paper elucidates the thermal behavior of an LED employing metal filled polymer matrix as thermal interface material (TIM) for an enhanced heat dissipation characteristic. Highly thermal conductive aluminum (Al) particles were incorporated in bisphenol A diglycidylether (DGEBA) epoxy matrix to study the effect of filler to polymer ratio on the thermal performance of high power LEDs. The curing behavior of DGEBA was studied by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The dispersion nature of the Al fillers in polymer matrix was verified with Field Emission Scanning Electron Microscope (FESEM). The thermal performance of synthesized Al filled polymer composite as TIM was tested with an LED employing thermal transient measurement technique. Comparing the filler to polymer ratio, the rise in junction temperature for 60 wt% Al filled composite was higher by 11.1 °C than 50 wt% Al filled composite at cured state. Observed also from the structure function analysis that the total thermal resistance was 10.96 K/W higher for 60 wt% Al filled composite compared to 50 wt% Al filled composite. On the other hand, a significant rise of 9.5 °C in the junction temperature between cured and uncured samples of 50 wt% Al filled polymer TIM was observed and hence the importance of curing process of metal filled polymer composite for effective heat dissipation is discussed extensively in this work.

P. Anithambigai; S. Shanmugan; D. Mutharasu; T. Zahner; D. Lacey

2014-01-01T23:59:59.000Z

465

Improving Switching Performance of Power MOSFETs Used in High Rep-Rate, Short Pulse, High-Power Pulsers  

SciTech Connect

As their switching and power handling characteristics improve, solid-state devices are finding new applications in pulsed power. This is particularly true of applications that require fast trains of short duration pulses. High voltage (600-1200V) MOSFETs are especially well suited for use in these systems, as they can switch at significant peak power levels and are easily gated on and off very quickly. MOSFET operation at the shortest pulse durations is not constrained by the intrinsic capabilities of the MOSFET, but rather by the capabilities of the gate drive circuit and the system physical layout. This project sought to improve MOSFET operation in a pulsed power context by addressing these issues. The primary goal of this project is to improve the switching performance of power MOSFETs for use in high rep-rate, short pulse, high-power applications by improving the design of the gate drive circuits and the circuit layouts used in these systems. This requires evaluation of new commercial gate drive circuits and upgrading the designs of LLNL-developed circuits. In addition, these circuits must be tested with the fastest available high-voltage power MOSFETs.

Cook, E G

2006-09-19T23:59:59.000Z

466

Multi-nozzle array spray cooling for large area high power devices in a closed loop system  

Science Journals Connector (OSTI)

Abstract A prototype of a closed loop system was built to study multi-nozzle array spray cooling on high-power, large-area electronic devices. Fifty-four nozzles with an in-lined array of 9 × 6 were applied to spray cool a simulated 6U electronic card using R134a. Simple drainage concepts were introduced to assist the drainage of both liquid and vapour on the heated surface. The results indicated a promising prospect of using a multi-nozzle array on large-area power electronics cooling. 16 kW heat was removed from the 6U card area by maintaining the mean surface temperature below 26.5  ° C . Heat transfer coefficient up to 2.8  × 10 4 W / m 2 K was obtained, and liquid usage fraction as high as 0.88 was achieved before CHF occurred. It was found that increasing nozzle pressure drop or flow rate enhanced heat transfer and gave better surface temperature uniformity. Chamber pressure significantly influenced mean surface temperature, but had no observable effects on surface temperature uniformity. The control of chamber pressure can maintain a constant temperature on the heated surface when heat load varied largely. The results also showed that the spray-to-spray interactions had inconspicuous effects on local surface temperatures but rather the distance from a location relative to the drainage outlets.

J.L. Xie; Y.B. Tan; T.N. Wong; F. Duan; K.C. Toh; K.F. Choo; P.K. Chan; Y.S. Chua

2014-01-01T23:59:59.000Z

467

Coherent versus incoherent sequential quantum measurements  

SciTech Connect

We compare a trade-off between knowledge and decoherence for the incoherent and coherent partial sequential compatible measurements on single-qubit systems. The individual partial measurement nondestructively monitors basis states of the system by single-qubit meter. For the same decoherence caused by this unbiased measurement, the individual coherent measurement gives more knowledge than the incoherent one. For identical sequential coherent measurements, knowledge accumulated not additively increases more slowly than for the incoherent measurements. The overall knowledge can be accumulated using an adaptive measurement strategy on the meters if the single-qubit coherence of meters is kept. On the other hand, preservation of the mutual qubit coherence between the meters necessary for the collective measurement strategy is not required. A loss of single-qubit coherence degrades the coherent measurements back to the incoherent ones. Since the decoherence caused by the measurement process is a quadratic function of knowledge extracted by the individual measurement, Zeno-like behavior can be observed for repetitive weak compatible measurements. This unconditional universal effect does not depend on any dynamics of the qubit and it is a direct consequence of optimally controlled sequential evolution of quantum information.

Filip, Radim [Department of Optics, Palacky University, 17. listopadu 1192/12, CZ-771 46 Olomouc (Czech Republic)

2011-03-15T23:59:59.000Z

468

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

SciTech Connect

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

469

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

SciTech Connect

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

470

Terahertz imaging of sub-wavelength particles with Zenneck surface waves  

SciTech Connect

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

471

Role of collisional broadening in Monte Carlo simulations of terahertz quantum cascade lasers  

SciTech Connect

Using a generalized version of Fermi's golden rule, collisional broadening is self-consistently implemented into ensemble Monte Carlo carrier transport simulations, and its effect on the transport and optical properties of terahertz quantum cascade lasers is investigated. The inclusion of broadening yields improved agreement with the experiment, without a significant increase of the numerical load. Specifically, this effect is crucial for a correct modeling at low biases. In the lasing regime, broadening can lead to significantly reduced optical gain and output power, affecting the obtained current-voltage characteristics.

Matyas, Alpar; Lugli, Paolo; Jirauschek, Christian [Institute for Nanoelectronics, Technische Universitaet Muenchen, D-80333 Munich (Germany)] [Institute for Nanoelectronics, Technische Universitaet Muenchen, D-80333 Munich (Germany)

2013-01-07T23:59:59.000Z

472

Equivalent circuit-level model and improvement of terahertz quantum cascade lasers  

Science Journals Connector (OSTI)

An equivalent circuit-level model of terahertz (THz) quantum cascade lasers (QCLs) is developed by using rate equations. This model can be employed to investigate the characteristics of THz QCLs accurately and to improve their design. We use the circuit-level model to analyse a new active structure, which can improve the performance of THz QCLs by means of enhancing carrier injection. The simulation result shows that THz QCLs with the new active structure have a much higher performance compared with conventional THz QCLs. The high-performance THz QCLs are expected to be operated at higher temperatures.

Wei Zhou; Shaobin Liu; Jie Wu; Xiaoliu Zhang; Wu Tang

2014-01-01T23:59:59.000Z

473

High-resolution emission spectra of pulsed terahertz quantum-cascade lasers  

SciTech Connect

The spectra of pulsed terahertz quantum-cascade lasers were measured with high spectral resolution. The characteristic line width at half maximum was 0.01 cm{sup -1}; it is controlled by laser temperature variations during the supply voltage pulse. It was shown that an increase in the laser temperature leads to a decrease in the emission frequency, which is caused by an increase in the effective refractive index of the active region. It was also found that a decrease in the supply voltage results in a decrease in the emission frequency, which is caused by a change in the energy of diagonal transitions between lasing levels.

Ikonnikov, A. V., E-mail: antikon@ipm.sci-nnov.ru; Antonov, A. V.; Lastovkin, A. A.; Gavrilenko, V. I. [Russian Academy of Sciences, Institute for Physics of Microstructures (Russian Federation); Sadof'ev, Yu. G.; Samal, N. [Trion Technology (United States)

2010-11-15T23:59:59.000Z

474

Propagation of terahertz electromagnetic wave in plasma with inhomogeneous collision frequency  

SciTech Connect

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

475

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

SciTech Connect

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

476

Kinetic transport theory with quantum coherence  

E-Print Network (OSTI)

We derive transport equations for fermions and bosons in spatially or temporally varying backgrounds with special symmetries, by use of the Schwinger-Keldysh formalism. In a noninteracting theory the coherence information is shown to be encoded in new singular shells for the 2-point function. Imposing this phase space structure to the interacting theory leads to a a self-consistent equation of motion for a physcial density matrix, including coherence and a well defined collision integral. The method is applied e.g. to demonstrate how an initially coherent out-of-equlibrium state approaches equlibrium through decoherence and thermalization.

Matti Herranen; Kimmo Kainulainen; Pyry M. Rahkila

2008-11-06T23:59:59.000Z

477

Coherence of magnetic resonators in a metamaterial  

SciTech Connect

The coherence of periodic magnetic resonators (MRs) under oblique incidence is studied using simulations. The correlated phase of interaction including both the retardation effect and relative phase difference between two MRs is defined, and it plays a key role in the MR interaction. The correlated phase is anisotropic, as is the coherence condition. The coherence condition is the same as the Wood's anomaly and verified by the Fano resonance. This study shows that the applications of the Fano resonance of periodic MRs will become widespread owing to achieving the Fano resonance simply by tuning the incident angle.

Hou, Yumin, E-mail: ymhou@pku.edu.cn [State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871 (China)] [State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871 (China)

2013-12-15T23:59:59.000Z

478

Observation of photoassisted polarization switching in BiFeO3 thin films probed by terahertz radiation  

E-Print Network (OSTI)

radiation Kouhei Takahashi and Masayoshi Tonouchia Institute of Laser Engineering, Osaka University, 2-6 Yamadaoka, Suita, Osaka 565-0871, Japan Received 16 October 2006; accepted 1 January 2007; published online film using terahertz radiation as the probe. The illumination of femtosecond laser pulses with a center

Tonouchi, Masayoshi

479

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.

480

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

Note: This page contains sample records for the topic "high-power coherent terahertz" from the National Library of EnergyBeta (NLEBeta).
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481

Scalable High-Power Redox Capacitors with Aligned Nanoforests of Crystalline MnO2 Nanorods by High Voltage Electrophoretic Deposition  

Science Journals Connector (OSTI)

Scalable High-Power Redox Capacitors with Aligned Nanoforests of Crystalline MnO2 Nanorods by High Voltage Electrophoretic Deposition ... The scalable nanomanufacturing process is demonstrated by roll-printing an aligned forest of ?-MnO2 nanorods on a large flexible substrate (1 inch by 1 foot). ...

Sunand Santhanagopalan; Anirudh Balram; Dennis Desheng Meng

2013-02-01T23:59:59.000Z

482

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

483

Journal of Power Sources 153 (2006) 6875 Numerical study of a flat-tube high power density solid oxide fuel cell  

E-Print Network (OSTI)

power density (HPD) solid oxide fuel cell (SOFC) is a geometry based on a tubular type SOFC: Flat-tube; High power density (HPD); Solid oxide fuel cell (SOFC); Simulation; Performance; Optimization 1. Introduction A solid oxide fuel cell (SOFC), like any other fuel cell, produces electrical

484

Journal of Power Sources 140 (2005) 331339 Numerical study of a flat-tube high power density solid oxide fuel cell  

E-Print Network (OSTI)

) solid oxide fuel cell (SOFC) is a new design developed by Siemens Westinghouse, based on their formerly.V. All rights reserved. Keywords: Flat-tube; High power density; Solid oxide fuel cell; Simulation; Heat oxide fuel cell Part I. Heat/mass transfer and fluid flow Yixin Lu1, Laura Schaefer, Peiwen Li2

485

Enhancing photovoltaic power by Fano-induced coherence  

SciTech Connect

We show that coherence induced by Fano interference can enhance power generated by a photovoltaic device as compared to the same system with no coherence. No additional external energy source is necessary to create such induced coherence. In the present model, coherence increases the flow of electrons through the load, which reduces radiative recombination and enhances cell power.

Svidzinsky, Anatoly A.; Dorfman, Konstantin E.; Scully, Marlan O. [Texas A and M University, College Station, Texas 77843, USA and Princeton University, Princeton, New Jersey 08544 (United States)

2011-11-15T23:59:59.000Z

486

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

487

Photosynthetic light harvesting: excitons and coherence  

Science Journals Connector (OSTI)

...Delocalization-enhanced long-range energy transfer between cryptophyte...Scholes. 2012 Coherent energy transfer under incoherent...Oppenheimer, Jr.]. New York, NY: McGraw-Hill Book...162 ) 78 Kasha, M . 1963 Energy transfer mechanisms and...

2014-01-01T23:59:59.000Z

488

Coherence and emergence of classical spacetime  

Science Journals Connector (OSTI)

Using the coherent-state representation we show that the classical Einstein equation for the Friedmann-Robertson-Walker cosmological model with a general minimal scalar field can be derived from the semiclassical quantum Einstein equation.

Sang Pyo Kim; Jeong-Young Ji; Hak-Soo Shin; Kwang-Sup Soh

1997-09-15T23:59:59.000Z

489

Coherence and transitivity of subtyping as entailment  

Science Journals Connector (OSTI)

...Copyright 2000 Article Coherence and transitivity of subtyping as entailment G Longo A K Milsted A2 S Soloviev A3 A LIENS(CNRS) and DMI, Ecole Normale Superieure......

G Longo; K Milsted; S Soloviev

2000-08-01T23:59:59.000Z

490

Phase-Conjugate Optical Coherence Tomography  

E-Print Network (OSTI)

We demonstrate a new type of optical coherence tomography using only classical resources to achieve results that are typically associated with quantum-enhanced metrology: factor-of-two axial resolution enhancement and ...

Shapiro, Jeffrey H.

491

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

492

Coherence Momentum in Second-Order Vectorial Coherence Theory of Stationary Electromagnetic Fields  

Science Journals Connector (OSTI)

In analog to the electromagnetic momentum, we introduce vector and tensor densities to the general coherence theory of vector electromagnetic fields, and present new conservation...

Wang, Wei; Takeda, Mitsuo

493

Coherence Momentum in Second-Order Vectorial Coherence Theory of Stationary Electromagnetic Fields  

Science Journals Connector (OSTI)

In analog to the electromagnetic momentum, we introduce vector and tensor densities to the general coherence theory of vector electromagnetic fields, and present new conservation laws...

Wang, Wei; Takeda, Mitsuo

494

Coherence Effects in Resonance Fluorescence  

Science Journals Connector (OSTI)

The crossed-level method of atomic spectroscopy is discussed and the angular distribution formula for both the incoherent and coherent resonance scattering is derived. The form of this distribution function, as given here, explicity displays the geometric factors depending on radiation propagation vectors. With the application to hydrogen in mind, the distribution function is expressed explicitly for single electron transitions with external fields possessing axial symmetry. The properties of the distribution function are discussed with emphasis on the case of unpolarized radiation. For the case of hydrogen there are two possible applications of major interest. The first concerns the possibility of a precision measurement of the 2p fine structure splitting and, hence, a determination of the fine structure constant. Explicit results for the shape and other properties of the resonance line with a uniform magnetic field obtained. The other application is concerned with the possibility of measuring the 2s-2p Lamb splitting. This requires an electric field parallel to the magnetic field. Unfortunately, the level crossings which are sensitive to the Lamb splitting cannot radiate sufficiently rapidly while those which do radiate appreciably occur at field strengths which are extremely insensitive to the Lamb splitting.

M. E. Rose and R. L. Carovillano

1961-05-15T23:59:59.000Z

495

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

496

Extended Coherence Time with Atom-Number Squeezed States  

SciTech Connect

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 Bose-Einstein condensate interferometry. We observe quantitative agreement with theory both for the degree of initial number squeezing as well as for prolonged coherence times.

Li Wei; Tuchman, Ari K.; Chien, H.-C.; Kasevich, Mark A. [Physics Department, Stanford University, Stanford, California 94305 (United States)

2007-01-26T23:59:59.000Z

497

Insertion of coherence requests for debugging a multiprocessor  

DOE Patents (OSTI)

A method and system are disclosed to insert coherence events in a multiprocessor computer system, and to present those coherence events to the processors of the multiprocessor computer system for analysis and debugging purposes. The coherence events are inserted in the computer system by adding one or more special insert registers. By writing into the insert registers, coherence events are inserted in the multiprocessor system as if they were generated by the normal coherence protocol. Once these coherence events are processed, the processing of coherence events can continue in the normal operation mode.

Blumrich, Matthias A. (Ridgefield, CT); Salapura, Valentina (Chappaqua, NY)

2010-02-23T23:59:59.000Z

498

Quantum Coherence in a Superfluid Josephson Junction  

SciTech Connect

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

499

Two-Photon Absorption and Coherence  

Science Journals Connector (OSTI)

We study the probabilities for two-photon absorption processes induced by both coherent and thermal light when acting on an atomic system. Calculations are performed with quantum electrodynamics, and we find results similar to those obtained with semiclassical methods; that is, the two-photon absorption probability depends on the statistical properties of the light used. This probability assumes its maximum value for coherent light.

S. Carusotto; G. Fornaca; E. Polacco

1967-05-25T23:59:59.000Z

500

Coherence and Two-Photon Absorption  

Science Journals Connector (OSTI)

A kinetic theory of the two-photon absorption from a single mode of the radiation field is presented. It is found that, in general, the rate of two-photon absorption depends on certain correlation functions, and hence on the coherence properties, of the field. The results are applied to the case of a pure coherent state and the case of a chaotic field.

P. Lambropoulos; C. Kikuchi; R. K. Osborn

1966-04-29T23:59:59.000Z