Sample records for ultrafast physics molecular

  1. Wavelet analysis of molecular dynamics: Efficient extraction of time-frequency information in ultrafast optical processes

    SciTech Connect (OSTI)

    Prior, Javier; Castro, Enrique [Departamento de Física Aplicada, Universidad Politécnica de Cartagena, Cartagena 30202 (Spain)] [Departamento de Física Aplicada, Universidad Politécnica de Cartagena, Cartagena 30202 (Spain); Chin, Alex W. [Theory of Condensed Matter Group, University of Cambridge, J J Thomson Avenue, Cambridge CB3 0HE (United Kingdom)] [Theory of Condensed Matter Group, University of Cambridge, J J Thomson Avenue, Cambridge CB3 0HE (United Kingdom); Almeida, Javier; Huelga, Susana F.; Plenio, Martin B. [Institut für Theoretische Physik, Albert-Einstein-Allee 11, Universität Ulm, D-89069 Ulm (Germany)] [Institut für Theoretische Physik, Albert-Einstein-Allee 11, Universität Ulm, D-89069 Ulm (Germany)

    2013-12-14T23:59:59.000Z

    New experimental techniques based on nonlinear ultrafast spectroscopies have been developed over the last few years, and have been demonstrated to provide powerful probes of quantum dynamics in different types of molecular aggregates, including both natural and artificial light harvesting complexes. Fourier transform-based spectroscopies have been particularly successful, yet “complete” spectral information normally necessitates the loss of all information on the temporal sequence of events in a signal. This information though is particularly important in transient or multi-stage processes, in which the spectral decomposition of the data evolves in time. By going through several examples of ultrafast quantum dynamics, we demonstrate that the use of wavelets provide an efficient and accurate way to simultaneously acquire both temporal and frequency information about a signal, and argue that this greatly aids the elucidation and interpretation of physical process responsible for non-stationary spectroscopic features, such as those encountered in coherent excitonic energy transport.

  2. Hydrogen Bond Migration between Molecular Sites Observed with Ultrafast 2D IR Chemical Exchange Spectroscopy

    E-Print Network [OSTI]

    Fayer, Michael D.

    Hydrogen Bond Migration between Molecular Sites Observed with Ultrafast 2D IR Chemical ExchangeVed: January 12, 2010 Hydrogen-bonded complexes between phenol and phenylacetylene are studied using ultrafast hydrogen bonding acceptor sites (phenyl or acetylene) that compete for hydrogen bond donors in solution

  3. Dynamics of Functionalized Surface Molecular Monolayers Studied with Ultrafast Infrared Vibrational Spectroscopy

    E-Print Network [OSTI]

    Fayer, Michael D.

    Dynamics of Functionalized Surface Molecular Monolayers Studied with Ultrafast Infrared Vibrational by excitation transfer and molecular reorientation. The HDTG experiments show no evidence of anisotropy decay of molecular monolayers depend on the structure and dynamics of the surface-attached molecules. New tools

  4. Non-adiabatic molecular dynamics simulation of ultrafast solar cell electron transfer

    E-Print Network [OSTI]

    confinement devices [1­5]. Solar cells of the Graetzel type [6,7] are based on dye sensitized nanocrystalline in solar cells, photocatalysis and photoelectrolysis. The electronic structure of the dye cell; Ultrafast electron transfer; Non-adiabatic molecular dynamics simulation; Dye sensitized titanium

  5. PHYSICAL REVIEW B 84, 094502 (2011) Nondeterministic ultrafast ground-state cooling of a mechanical resonator

    E-Print Network [OSTI]

    2011-01-01T23:59:59.000Z

    proposed a ground-state cooling scheme of an MR in an optomechanical system by controlling the opticalPHYSICAL REVIEW B 84, 094502 (2011) Nondeterministic ultrafast ground-state cooling of a mechanical Research Center, Beijing 100084, China 2 Department of Theoretical Physics and History of Science

  6. Ultraslow dissociation of the H{sub 2}{sup +} molecular ion via two-color ultrafast laser pulses

    SciTech Connect (OSTI)

    Moser, B.; Gibson, G. N. [Department of Physics, University of Connecticut, Storrs, Connecticut 06269 (United States)

    2009-10-15T23:59:59.000Z

    We report a mode of dissociative ionization in an intense two-color laser field. When bond softened by the superposition of 800 and 400 nm ultrafast laser pulses in a narrow intensity range, H{sub 2}{sup +} molecular ions experience ultraslow dissociation. This near-zero kinetic-energy release is supported by theoretical simulations and two-color field-dressed adiabatic potential curves. Furthermore, we show that the shift to lower energy of a known bond-softened peak can be explained by the influence of a two-color field-induced potential well. Such ultraslow dissociation can facilitate ultrafast time-resolved spectroscopy of molecules.

  7. Coherent lattice and molecular dynamics in ultrafast single-shot spectroscopy

    E-Print Network [OSTI]

    Poulin, Peter Roland, 1973-

    2005-01-01T23:59:59.000Z

    This thesis focuses on the development, refinement, and application of dual- echelon single-shot ultrafast spectroscopy to the study of coherent nuclear motion in condensed phase systems. The general principles of the ...

  8. AGN-driven winds on all scales in Markarian 231: from hot nuclear ultra-fast up to kpc-extended molecular outflow

    E-Print Network [OSTI]

    Feruglio, C; Carniani, S; Piconcelli, E; Zappacosta, L; Bongiorno, A; Cicone, C; Maiolino, R; Marconi, A; Menci, N; Puccetti, S; Veilleux, S

    2015-01-01T23:59:59.000Z

    We present the best sensitivity and angular resolution maps of the molecular disk and outflow of Mrk231, obtained with IRAM/PdBI, and an analysis of archival Chandra and NuSTAR data. We constrain the physical properties of both the molecular disk and outflow, the presence of a highly-ionized ultra-fast nuclear wind, and their connection. The CO(2-1) outflow has a size of ~1 kpc, and extends in all directions around the nucleus, being more prominent along the south-west to north-east direction, suggesting a wide-angle biconical geometry. Its maximum projected velocity is nearly constant out to ~1 kpc, thus implying that the density of the outflowing material must decrease from the nucleus outwards as ~ r^-2. This suggests that either a large part of the gas leaves the flow during its expansion, or that the bulk of the outflow has not yet reached ~1 kpc, implying a limit on its age of ~ 1 Myr. The mass and energy rates of the molecular outflow are dM/dt(OF)=[500-1000] Msun/yr and dE(kin,OF)/dt=[7-10] 10^43 erg/...

  9. Ultrafast Excited-State Dynamics in the Green Fluorescent Protein Variant S65T/ H148D. 2. Unusual Photophysical Properties

    E-Print Network [OSTI]

    Boxer, Steven G.

    Ultrafast Excited-State Dynamics in the Green Fluorescent Protein Variant S65T/ H148D. 2. Unusual, California 94305-5080, and Institute of Molecular Biology and Department of Physics, UniVersity of Oregon of this variant at pH 5.6 by ultrafast fluorescence upconversion spectroscopy. Following excitation at 400 nm

  10. Distribution Category: Atomic, Molecular, and Chemical Physics

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

    Atomic, Molecular, and Chemical Physics (UC-411) ARGONNE NATIONAL LABORATORY 9700 South Cass Avenue Argonne, TIlinois 60439 ANLI APSILS-151 RESULTS OF DESIGN CALCULATIONS FOR THE...

  11. Measuring molecular electric dipoles using trapped atomic ions and ultrafast laser pulses

    E-Print Network [OSTI]

    Jordi Mur-Petit; Juan José García-Ripoll

    2015-01-12T23:59:59.000Z

    We study a hybrid quantum system composed of an ion and an electric dipole. We show how a trapped ion can be used to measure the small electric field generated by a classical dipole. We discuss the application of this scheme to measure the electric dipole moment of cold polar molecules, whose internal state can be controlled with ultrafast laser pulses, by trapping them in the vicinity of a trapped ion.

  12. Comparative investigation of third- and fifth-harmonic generation in atomic and molecular gases driven by midinfrared ultrafast laser pulses

    SciTech Connect (OSTI)

    Ni Jielei; Yao Jinping; Zeng Bin; Chu Wei; Li Guihua; Zhang Haisu; Jing Chenrui [State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, P.O. Box 800-211, Shanghai 201800 (China); Graduate School of the Chinese Academy of Sciences, Beijing 100039 (China); Chin, S. L. [Department of Physics, Engineering Physics and Optics, and Center for Optics, Photonics and Laser (COPL), Laval University, Laval, Quebec, G1K 7P4 (Canada); Cheng, Y.; Xu, Z. [State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, P.O. Box 800-211, Shanghai 201800 (China)

    2011-12-15T23:59:59.000Z

    We report on the comparative experimental investigation on third- and fifth-harmonic generation (THG and FHG) in atomic and molecular gases driven by midinfrared ultrafast laser pulses at a wavelength of {approx}1500 nm. We observe that the conversion efficiencies of both the THG and FHG processes saturate at similar peak intensities close to {approx}1.5 x 10{sup 14} W/cm{sup 2} for argon, nitrogen, and air, whose ionization potentials are close to each other. Near the saturation intensity, the ratio of yields of the FHG and THG reaches {approx}10{sup -1} for all the gases. Our results show that high-order Kerr effect seems to exist; however, contribution from the fourth-order Kerr refractive index coefficient alone is insufficient to balance the Kerr self-focusing without the assistance of plasma generation.

  13. Ultrafast Energy-Electron Transfer Cascade in a Multichromophoric Light-Harvesting Molecular Square

    E-Print Network [OSTI]

    van Stokkum, Ivo

    and electron-transfer pathways, and chromophoric heterogeneity. Temperature-dependent time-resolved emission in the fields of molecular recognition,9,10 sensing,6,9 catalysis,11 and electrochemical or photochemical

  14. Ultrafast probing of ejection dynamics of Rydberg atoms and molecular fragments from electronically excited helium nanodroplets

    SciTech Connect (OSTI)

    Buenermann, Oliver; Kornilov, Oleg; Neumark, Daniel M. [Ultrafast X-ray Science Laboratory, Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Department of Chemistry, University of California, Berkeley, California 94720 (United States); Haxton, Daniel J.; Gessner, Oliver [Ultrafast X-ray Science Laboratory, Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Leone, Stephen R. [Ultrafast X-ray Science Laboratory, Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Department of Chemistry, University of California, Berkeley, California 94720 (United States); Department of Physics, University of California, Berkeley, California 94720 (United States)

    2012-12-07T23:59:59.000Z

    The ejection dynamics of Rydberg atoms and molecular fragments from electronically excited helium nanodroplets are studied with time-resolved extreme ultraviolet ion imaging spectroscopy. At excitation energies of 23.6 {+-} 0.2 eV, Rydberg atoms in n= 3 and n= 4 states are ejected on different time scales and with significantly different kinetic energy distributions. Specifically, n= 3 Rydberg atoms are ejected with kinetic energies as high as 0.85 eV, but their appearance is delayed by approximately 200 fs. In contrast, n= 4 Rydberg atoms appear within the time resolution of the experiment with considerably lower kinetic energies. Major features in the Rydberg atom kinetic energy distributions for both principal quantum numbers can be described within a simple elastic scattering model of localized perturbed atomic Rydberg atoms that are expelled from the droplet due to their repulsive interaction with the surrounding helium bath. Time-dependent kinetic energy distributions of He{sub 2}{sup +} and He{sub 3}{sup +} ions are presented that support the formation of molecular ions in an indirect droplet ionization process and the ejection of neutral Rydberg dimers on a similar time scale as the n= 3 Rydberg atoms.

  15. Circularly Polarized X Rays: Another Probe of Ultrafast Molecular Decay Dynamics

    SciTech Connect (OSTI)

    Travnikova, Oksana; Lindblad, Andreas; Nicolas, Christophe; Soederstroem, Johan; Kimberg, Victor; Miron, Catalin [Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, B.P. 48, F-91192 Gif-sur-Yvette Cedex (France); Liu Jicai; Gel'mukhanov, Faris [Department of Theoretical Chemistry, Roslagstullsbacken 15, Royal Institute of Technology, S-106 91 Stockholm (Sweden)

    2010-12-03T23:59:59.000Z

    Dissociative nuclear motion in core-excited molecular states leads to a splitting of the fragment Auger lines: the Auger-Doppler effect. We present here for the first time experimental evidence for an Auger-Doppler effect following F1s{yields}a{sub 1g}* inner-shell excitation by circularly polarized x rays in SF{sub 6}. In spite of a uniform distribution of the dissociating S-F bonds near the polarization plane of the light, the intersection between the subpopulation of molecules selected by the core excitation with the cone of dissociation induces a strong anisotropy in the distribution of the S-F bonds that contributes to the scattering profile measured in the polarization plane.

  16. Ultrafast Core-Hole Induced Dynamics in Water

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

    isotope substitution experiments and molecular dynamics simulations, researchers from Sweden, Germany, and the U.S. have shown that the ultrafast (0- to 10-fs) dissociation...

  17. Spatiotemporal Imaging of Ultrafast Molecular Motion: Collapse and Revival of the D{sub 2}{sup +} Nuclear Wave Packet

    SciTech Connect (OSTI)

    Ergler, Th.; Rudenko, A.; Zrost, K.; Schroeter, C. D.; Moshammer, R.; Ullrich, J. [Max-Planck-Institut fuer Kernphysik, D-69029 Heidelberg (Germany); Feuerstein, B. [Max-Planck-Institut fuer Kernphysik, D-69029 Heidelberg (Germany); Physikalisches Institut, Universitaet Heidelberg, 69120 Heidelberg (Germany)

    2006-11-10T23:59:59.000Z

    We report on a real-time imaging of the ultrafast D{sub 2}{sup +} rovibrational nuclear wave-packet motion performed using a combination of a pump-probe setup with 7 fs laser pulses and a 'reaction-microscope' spectrometer. We observe fast dephasing (collapse) of the vibrational wave packet and its subsequent revival and prove rotational excitation in ultrashort laser pulses. Channel-selective Fourier analysis of the wave packet's long-term ({approx}3000 fs) evolution allows us to resolve its individual constituents, revealing unique information on the mechanisms of strong-field ionization and dissociation.

  18. CYBERNETICAL PHYSICS AND CONTROL OF MOLECULAR SYSTEMS1

    E-Print Network [OSTI]

    1 CYBERNETICAL PHYSICS AND CONTROL OF MOLECULAR SYSTEMS1 Alexander Fradkov, Mikhail Ananyevsky. INTRODUCTION. PHYSICS AND CYBERNETICS Looking into the past. Encyclopedias define physics as the science studying the Nature, specifically its basic and most universal properties. The age of physics is about two

  19. Physics with fast molecular-ion beams

    SciTech Connect (OSTI)

    Kanter, E.P.

    1980-01-01T23:59:59.000Z

    Fast (MeV) molecular-ion beams provide a unique source of energetic projectile nuclei which are correlated in space and time. The recognition of this property has prompted several recent investigations of various aspects of the interactions of these ions with matter. High-resolution measurements on the fragments resulting from these interactions have already yielded a wealth of new information on such diverse topics as plasma oscillations in solids and stereochemical structures of molecular ions as well as a variety of atomic collision phenomena. The general features of several such experiments will be discussed and recent results will be presented.

  20. University of Wisconsin-Milwaukee Dept. of Physics

    E-Print Network [OSTI]

    Saldin, Dilano

    -induced Reactions: From Strong-field Physics to Ultrafast Photochemistry Artem Rudenko Assistant Professor, Dept

  1. Ultrafast gas switching experiments

    SciTech Connect (OSTI)

    Frost, C.A.; Martin, T.H.; Patterson, P.E.; Rinehart, L.F.; Rohwein, G.J.; Roose, L.D.; Aurand, J.F.; Buttram, M.T.

    1996-11-01T23:59:59.000Z

    We describe recent experiments which studied the physics of ultrafast gas breakdown under the extreme overvoltages which occur when a high pressure gas switch is pulse charged to hundreds of kV in 1 ns or less. The highly overvolted peaking gaps produce powerful electromagnetic pulses with risetimes < 100 ps which can be used for ultrawideband radar systems, particle accelerators, laser drivers, bioelectromagnetic studies, electromagnetic effects testing, and for basic studies of gas breakdown physics. We have produced and accurately measured pulses with 50 to 100 ps risetimes to peak levels of 75 to 160 kV at pulse repetition frequencies (PRF) to I kHz. A unique gas switch was developed to hold off hundreds of kV with parasitic inductance less than I nH. An advanced diagnostic system using Fourier compensation was developed to measure single-shot risetimes below 35 ps. The complete apparatus is described and wave forms are presented. The measured data are compared with a theoretical model which predicts key features including dependence on gas species and pressure. We have applied this technology to practical systems driving ultrawideband radiating antennas and bounded wave simulators. For example, we have developed a thyristor/pulse transformer based system using a highly overvolted cable switch. This pulser driving a Sandia- designed TEM cell, provides an ultra wideband impulse with < 200 ps risetime to the test object at a PRF > 1 kHz at > 100 kV/m E field.

  2. Ultrafast Magnetic Light

    E-Print Network [OSTI]

    Makarov, Sergey V; Krasnok, Alexander E; Belov, Pavel A

    2015-01-01T23:59:59.000Z

    We propose a novel concept for efficient dynamic tuning of optical properties of a high refractive index subwavelength nanoparticle with a magnetic Mie-type resonance by means of femtosecond laser radiation. This concept is based on ultrafast generation of electron-hole plasma within such nanoparticle, drastically changing its transient dielectric permittivity. This allows to manipulate by both electric and magnetic nanoparticle responses, resulting in dramatic changes of its extinction cross section and scattering diagram. Specifically, we demonstrate the effect of ultrafast switching-on a Huygens source in the vicinity of the magnetic dipole resonance. This approach enables to design ultrafast and compact optical switchers and modulators based on the "ultrafast magnetic light" concept.

  3. Ultrafast studies of solution dynamics

    SciTech Connect (OSTI)

    Woodruff, W.H.; Dyer, R.B. [Los Alamos National Lab., NM (United States); Callender, R.H. [City Univ. of New York, NY (United States). Dept. of Physics

    1997-10-01T23:59:59.000Z

    This is the final report of a one-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). Fast chemical dynamics generally must be initiated photochemically. This limits the applicability of modern laser methods for following the structural changes that occur during chemical and biological reactions to those systems that have an electronic chromophore that has a significant yield of photoproduct when excited. This project has developed a new and entirely general approach to ultrafast initiation of reactions in solution: laser-induced temperature jump (T-jump). The results open entire new fields of study of ultrafast molecular dynamics in solution. The authors have demonstrated the T-jump technique on time scales of 50 ps and longer, and have applied it to study of the fast events in protein folding. They find that a general lifetime of alpha-helix formation is ca 100 ns, and that tertiary folds (in apomyoglobin) form in ca 100 {mu}s.

  4. Coherent ultrafast pulse synthesis between an optical parametric oscillator and a laser

    E-Print Network [OSTI]

    Coherent ultrafast pulse synthesis between an optical parametric oscillator and a laser Jinghua Sun* and Derryck T. Reid Ultrafast Optics Group, School of Engineering and Physical Sciences, Heriot 13, 2009 We have demonstrated coherent pulse synthesis between the carrier-envelope, phase

  5. Ultrafast Spectroscopy of Correlated Electron Systems

    E-Print Network [OSTI]

    Schmid, Benjamin Andrew

    2009-01-01T23:59:59.000Z

    full, non-zero bandwidth of an ultrafast pulse with itself.amplifier delivers ultrafast pulses of 45 fs at a repetitionthe “rectification” of an ultrafast optical pulse will have

  6. Faculty Position Atomic, Molecular and Optical Physics The Columbia University Department of Physics seeks to appoint an assistant professor

    E-Print Network [OSTI]

    Qian, Ning

    Faculty Position Atomic, Molecular and Optical Physics The Columbia University Department November 1, 2014 and continue until the position is filled. Columbia University is an Equal Opportunity research program, continuing the long Columbia record of outstanding accomplishment in science. Applicants

  7. Plasmonic enhanced ultrafast switch.

    SciTech Connect (OSTI)

    Subramania,Ganapathi Subramanian; Reno, John Louis; Passmore, Brandon Scott; Harris, Tom.; Shaner, Eric Arthur; Barrick, Todd A.

    2009-09-01T23:59:59.000Z

    Ultrafast electronic switches fabricated from defective material have been used for several decades in order to produce picosecond electrical transients and TeraHertz radiation. Due to the ultrashort recombination time in the photoconductor materials used, these switches are inefficient and are ultimately limited by the amount of optical power that can be applied to the switch before self-destruction. The goal of this work is to create ultrafast (sub-picosecond response) photoconductive switches on GaAs that are enhanced through plasmonic coupling structures. Here, the plasmonic coupler primarily plays the role of being a radiation condenser which will cause carriers to be generated adjacent to metallic electrodes where they can more efficiently be collected.

  8. PHYSICS OF CHEMORECEPTION HOWARD C. BERG AND EDWARD M. PURCELL, Department ofMolecular,

    E-Print Network [OSTI]

    Voigt, Chris

    PHYSICS OF CHEMORECEPTION HOWARD C. BERG AND EDWARD M. PURCELL, Department ofMolecular, Cellular, and Developmental Biology, University ofColorado, Boulder, Colorado 80309 and the Department ofPhysics, Harvard. In these circumstances, what are the physical limitations on the cell's ability to sense and respond to changes in its

  9. Ptychographic ultrafast pulse reconstruction

    E-Print Network [OSTI]

    Spangenberg, D; Brügmann, M H; Feurer, T

    2014-01-01T23:59:59.000Z

    We demonstrate a new ultrafast pulse reconstruction modality which is somewhat reminiscent of frequency resolved optical gating but uses a modified setup and a conceptually different reconstruction algorithm that is derived from ptychography. Even though it is a second order correlation scheme it shows no time ambiguity. Moreover, the number of spectra to record is considerably smaller than in most other related schemes which, together with a robust algorithm, leads to extremely fast convergence of the reconstruction.

  10. Spectroscopy of complex molecular systems: Physics on an exciton...

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

    of perfect molecular crystals, in which case the excitons are simple Bloch waves of excitation. Over the years, it has become apparent that also less regular structures carry...

  11. To appear in Journal of Computational Physics Parallel Discrete Molecular Dynamics Simulation

    E-Print Network [OSTI]

    Herbordt, Martin

    To appear in Journal of Computational Physics Parallel Discrete Molecular Dynamics Simulation and Automated Design Laboratory Department of Electrical and Computer Engineering Boston University; Boston, MA 02215 www.bu.edu/caadlab; email: azkhan@bu.edu, herbordt@bu.edu Abstract: Discrete molecular dynamics

  12. Ultrafast optical parametric processes in photonic crystal fibers: fundamentals and applications

    E-Print Network [OSTI]

    Gu, Chenji

    2012-01-01T23:59:59.000Z

    of ultrafast optical pulses . . . . . . . . .copropagating ultrafast optical pulses”, Appl. Phys. Lett.Additionally, the ultrafast pump pulses can experience

  13. Ultrafast Transformations in Superionic Nanocrystals

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What'sis Taking Over OurThe Iron Spin TransitionProgram |FrankUltrafast Spectroscopy ofUltrafastUltrafast

  14. Ultrafast Transformations in Superionic Nanocrystals

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What'sis Taking Over OurThe Iron Spin TransitionProgram |FrankUltrafast SpectroscopyUltrafastUltrafast

  15. Ultrafast scanning tunneling microscopy

    SciTech Connect (OSTI)

    Botkin, D.A. [California Univ., Berkeley, CA (United States). Dept. of Physics]|[Lawrence Berkeley Lab., CA (United States)

    1995-09-01T23:59:59.000Z

    I have developed an ultrafast scanning tunneling microscope (USTM) based on uniting stroboscopic methods of ultrafast optics and scanned probe microscopy to obtain nanometer spatial resolution and sub-picosecond temporal resolution. USTM increases the achievable time resolution of a STM by more than 6 orders of magnitude; this should enable exploration of mesoscopic and nanometer size systems on time scales corresponding to the period or decay of fundamental excitations. USTM consists of a photoconductive switch with subpicosecond response time in series with the tip of a STM. An optical pulse from a modelocked laser activates the switch to create a gate for the tunneling current, while a second laser pulse on the sample initiates a dynamic process which affects the tunneling current. By sending a large sequence of identical pulse pairs and measuring the average tunnel current as a function of the relative time delay between the pulses in each pair, one can map the time evolution of the surface process. USTM was used to measure the broadband response of the STM`s atomic size tunnel barrier in frequencies from tens to hundreds of GHz. The USTM signal amplitude decays linearly with the tunnel junction conductance, so the spatial resolution of the time-resolved signal is comparable to that of a conventional STM. Geometrical capacitance of the junction does not appear to play an important role in the measurement, but a capacitive effect intimately related to tunneling contributes to the measured signals and may limit the ultimate resolution of the USTM.

  16. Ultrafast studies of organometallic photochemistry: the mechanism of carbon-hydrogen bond activation in solution

    E-Print Network [OSTI]

    Broomberg, Steven E.

    2010-01-01T23:59:59.000Z

    watts [2]. These "ultrafast pulses" can be used to resolveof the directions that ultrafast pulse research has taken inand a separate ultrafast visible pulse to detect ultrafast

  17. Ultrafast Switching of Coherent Electronic Excitation: Great Promise for Reaction Control

    E-Print Network [OSTI]

    Peinke, Joachim

    With the advent of femtosecond laser pulses the temporal aspect of the interplay of light and molecular dynamics pulses [4] are the suitable tools to exert microscopic control on molecular dynamics at the quantum levelUltrafast Switching of Coherent Electronic Excitation: Great Promise for Reaction Control

  18. Ultrafast optics For optics and photonics course,

    E-Print Network [OSTI]

    Palffy-Muhoray, Peter

    ultrafast and ultrashort generally describe pulses of widths in the nanosecond to femtosecond, or shorterUltrafast optics For optics and photonics course, Spring 2012 By :Alireza Moheghi Ultrafast optics, regimes. · Interest in ultrashort optical pulses began with the invention of the laser, · Ultrashort

  19. High-Pulse-Energy Ultrafast Laser for

    E-Print Network [OSTI]

    Painter, Kevin

    High-Pulse-Energy Ultrafast Laser for Spectroscopy & Micromachining PROBLEM THIS TECHNOLOGY SOLVES. In addition to the OPO, a custom designed ultrafast pump source, provides high pulse energy (.res.hw.ac.uk Professor Derryck Reid (Principal Investigator) www.ultrafast.hw.ac.uk BENEFITS & APPLICATIONS: · High pulse

  20. MOLECULAR PHYSICS, 1999, VOL. 97, NO. 7, 897 905 Dynamics and hydrogen bonding in liquid ethanol

    E-Print Network [OSTI]

    Saiz, Leonor

    MOLECULAR PHYSICS, 1999, VOL. 97, NO. 7, 897± 905 Dynamics and hydrogen bonding in liquid ethanol L of liquid ethanol at three temperatures have been carried out. The hydrogen bonding states of ethanol measurements of the frequency-dependent dielectric permittivity of liquid ethanol. 1. Introduction A detailed

  1. Ultrafast scanning probe microscopy

    DOE Patents [OSTI]

    Weiss, Shimon (El Cerrito, CA); Chemla, Daniel S. (Kensington, CA); Ogletree, D. Frank (El Cerrito, CA); Botkin, David (San Francisco, CA)

    1995-01-01T23:59:59.000Z

    An ultrafast scanning probe microscopy method for achieving subpicosecond-temporal resolution and submicron-spatial resolution of an observation sample. In one embodiment of the present claimed invention, a single short optical pulse is generated and is split into first and second pulses. One of the pulses is delayed using variable time delay means. The first pulse is then directed at an observation sample located proximate to the probe of a scanning probe microscope. The scanning probe microscope produces probe-sample signals indicative of the response of the probe to characteristics of the sample. The second pulse is used to modulate the probe of the scanning probe microscope. The time delay between the first and second pulses is then varied. The probe-sample response signal is recorded at each of the various time delays created between the first and second pulses. The probe-sample response signal is then plotted as a function of time delay to produce a cross-correlation of the probe sample response. In so doing, the present invention provides simultaneous subpicosecond-temporal resolution and submicron-spatial resolution of the sample.

  2. Ultrafast scanning probe microscopy

    DOE Patents [OSTI]

    Weiss, S.; Chemla, D.S.; Ogletree, D.F.; Botkin, D.

    1995-05-16T23:59:59.000Z

    An ultrafast scanning probe microscopy method is described for achieving subpicosecond-temporal resolution and submicron-spatial resolution of an observation sample. In one embodiment of the present claimed invention, a single short optical pulse is generated and is split into first and second pulses. One of the pulses is delayed using variable time delay means. The first pulse is then directed at an observation sample located proximate to the probe of a scanning probe microscope. The scanning probe microscope produces probe-sample signals indicative of the response of the probe to characteristics of the sample. The second pulse is used to modulate the probe of the scanning probe microscope. The time delay between the first and second pulses is then varied. The probe-sample response signal is recorded at each of the various time delays created between the first and second pulses. The probe-sample response signal is then plotted as a function of time delay to produce a cross-correlation of the probe sample response. In so doing, the present invention provides simultaneous subpicosecond-temporal resolution and submicron-spatial resolution of the sample. 6 Figs.

  3. Ultrafast Transformations in Superionic Nanocrystals

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What'sis Taking Over OurThe Iron Spin TransitionProgram |FrankUltrafast Spectroscopy ofUltrafast

  4. Ultrafast Transformations in Superionic Nanocrystals

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What'sis Taking Over OurThe Iron Spin TransitionProgram |FrankUltrafast SpectroscopyUltrafast

  5. Ultrafast magnetization dynamics in diluted magnetic semiconductors This article has been downloaded from IOPscience. Please scroll down to see the full text article.

    E-Print Network [OSTI]

    Boyer, Edmond

    Ultrafast magnetization dynamics in diluted magnetic semiconductors This article has been of Physics Ultrafast magnetization dynamics in diluted magnetic semiconductors O Morandi1,3 , P-A Hervieux2 of the magnetization in diluted magnetic semiconductor quantum wells after weak laser excitation. Based on the pseudo

  6. Ultrafast optical pulse shaping: A tutorial review Andrew M. Weiner

    E-Print Network [OSTI]

    Purdue University

    Ultrafast optical pulse shaping: A tutorial review Andrew M. Weiner Purdue University, School 2011 Keywords: Ultrafast optics Pulse shaping Femtosecond optics Coherent control Optical signal programmable reshapingof ultrafast pulses, or generation of arbitrary optical waveforms, according to user

  7. Stabilized Ultrafast Pulse Generation and Optical Frequency Combs Techniques

    E-Print Network [OSTI]

    Van Stryland, Eric

    Stabilized Ultrafast Pulse Generation and Optical Frequency Combs ­ Techniques and Applications Diodes ­ Review Ultrafast Dynamics ­ Breathing Mode (Dispersion Managed Cavity) · High Pulse Energy to Make Short Pulses - Review Ultrafast Dynamics- - Dispersion Managed (Breathing Mode) MLL #12

  8. Novel Applications of Ultrafast Laser

    E-Print Network [OSTI]

    Dantus, Marcos

    21 Novel Applications of Ultrafast Laser Spectroscopy Professor of chemistry and Adjunct Professor LASER PULSESare considered photonic reagents that can be used to study and control chemistry by our group. We are engaged in developing the laser technology as well as the novel applications that become

  9. MAUI: Modeling, Analysis, and Ultrafast Imaging | Argonne National...

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

    Data Science Modeling and Simulation Multimodal Imaging MAUI: Modeling, Analysis, and Ultrafast Imaging MAUI: Modeling, Analysis, and Ultrafast Imaging Project Goals...

  10. Ultrafast Phenomena XIV, pp. 650-654 , Springer, Berlin (2005). 650 Ultrafast Dynamics of Light Transmission

    E-Print Network [OSTI]

    Peinke, Joachim

    of ultrafast pulse propagation through nano-hole arrays reported a 10-fs delay in transmission [6 of ultrafast light propagation through plasmonic nano-crystals using light pulses much shorter than the SPPUltrafast Phenomena XIV, pp. 650-654 , Springer, Berlin (2005). 650 Ultrafast Dynamics of Light

  11. NANO EXPRESS Open Access Ultrafast nano-oscillators based on interlayer-

    E-Print Network [OSTI]

    Li, Teng

    NANO EXPRESS Open Access Ultrafast nano-oscillators based on interlayer- bridged carbon nanoscrolls nano-oscillators based on carbon nanoscrolls (CNSs) using molecular dynamics simulations. Initiated of gigahertz. We demonstrate an effective strategy to reduce the dissipation of the CNS-based nano

  12. Investigations of ultrafast nuclear response induced by resonant and nonresonant laser pulses

    E-Print Network [OSTI]

    Kumar, Anand T.N.

    Investigations of ultrafast nuclear response induced by resonant and nonresonant laser pulses Anand by ultrashort laser pulses interacting with a two electronic level molecular system. Fully quantum mechanical to implement. The behavior of the first two moments with respect to various parameters such as the pulse

  13. Ultrafast infrared studies of chemical reaction dynamics in room-temperature liquids

    E-Print Network [OSTI]

    Yang, H.

    2011-01-01T23:59:59.000Z

    ultrafast pulses ..analyses of the ultrafast pulses. (a) A spectral analysis ofExperimentally, an ultrafast UV pulse dissociates a photo

  14. PHYSICAL REVIEW E 84, 021907 (2011) Effectiveness of beads for tracking small-scale molecular motor dynamics

    E-Print Network [OSTI]

    2011-01-01T23:59:59.000Z

    PHYSICAL REVIEW E 84, 021907 (2011) Effectiveness of beads for tracking small-scale molecular motor into molecular motor dynamics are increasingly focused on small-scale features of the motor's motion. We define to the motor. We find that the best parameter choice depends on the objective of the experiments, and give

  15. Delayed Ultrafast X-ray Auger Probing (DUXAP) of Nucleobase Ultraviolet Photoprotection

    E-Print Network [OSTI]

    McFarland, B K; Miyabe, S; Tarantelli, F; Aguilar, A; Berrah, N; Bostedt, C; Bozek, J; Bucksbaum, P H; Castagna, J C; Coffee, R; Cryan, J; Fang, L; Feifel, R; Gaffney, K; Glownia, J; Martinez, T; Mucke, M; Murphy, B; Natan, A; Osipov, T; Petrovic, V; Schorb, S; Schultz, Th; Spector, L; Swiggers, M; Tenney, I; Wang, S; White, W; White, J; Gühr, M

    2013-01-01T23:59:59.000Z

    We present a new method for ultrafast spectroscopy of molecular photoexcited dynamics. The technique uses a pair of femtosecond pulses: a photoexcitation pulse initiating excited state dynamics followed by a soft x-ray (SXR) probe pulse that core ionizes certain atoms inside the molecule. We observe the Auger decay of the core hole as a function of delay between the photoexcitation and SXR pulses. The core hole decay is particularly sensitive to the local valence electrons near the core and shows new types of propensity rules, compared to dipole selection rules in SXR absorption or emission spectroscopy. We apply the delayed ultrafast x-ray Auger probing (DUXAP) method to the specific problem of nucleobase photoprotection to demonstrate its potential. The ultraviolet photoexcited \\pi\\pi* states of nucleobases are prone to chemical reactions with neighboring bases. To avoid this, the single molecules funnel the \\pi\\pi* population to lower lying electronic states on an ultrafast timescale under violation of the...

  16. Femtosecond pulse imaging: ultrafast optical oscilloscope

    E-Print Network [OSTI]

    Fainman, Yeshaiahu

    Femtosecond pulse imaging: ultrafast optical oscilloscope P. C. Sun, Y. T. Mazurenko,* and Y as well as our ability to detect the shape of the ul- trashort pulses that can be seen as an ultrafast 12, 1996 A nonlinear optical processor that is capable of real-time conversion of a femtosecond pulse

  17. Ultrafast Strong-Field Vibrational Dynamics Studied by Femtosecond Extreme-Ultraviolet Transient Absorption Spectroscopy

    E-Print Network [OSTI]

    Hosler, Erik Robert

    2013-01-01T23:59:59.000Z

    to yield a compressed, ultrafast pulse close to the originalspectral width of the ultrafast optical pulses, delivering

  18. Ultrafast, high precision gated integrator

    SciTech Connect (OSTI)

    Wang, X.

    1995-01-01T23:59:59.000Z

    An ultrafast, high precision gated integrator has been developed by introducing new design approaches that overcome the problems associated with earlier gated integrator circuits. The very high speed is evidenced by the output settling time of less than 50 ns and 20 MHz input pulse rate. The very high precision is demonstrated by the total output offset error of less than 0.2mV and the output droop rate of less than 10{mu}V/{mu}s. This paper describes the theory of this new gated integrator circuit operation. The completed circuit test results are presented.

  19. Ultrafast Transformations in Superionic Nanocrystals

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What'sis Taking Over OurThe Iron Spin TransitionProgram |FrankUltrafast Spectroscopy

  20. Ultrafast Transformations in Superionic Nanocrystals

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of ScienceandMesa del SolStrengthening aTurbulence may bedieselsummerFact SheetsUltrafastSpectroscopy

  1. Ultrafast pulsed laser utilizing broad bandwidth laser glass

    DOE Patents [OSTI]

    Payne, Stephen A. (Castro Valley, CA); Hayden, Joseph S. (Clarks Summit, PA)

    1997-01-01T23:59:59.000Z

    An ultrafast laser uses a Nd-doped phosphate laser glass characterized by a particularly broad emission bandwidth to generate the shortest possible output pulses. The laser glass is composed primarily of P.sub.2 O.sub.5, Al.sub.2 O.sub.3 and MgO, and possesses physical and thermal properties that are compatible with standard melting and manufacturing methods. The broad bandwidth laser glass can be used in modelocked oscillators as well as in amplifier modules.

  2. Ultrafast pulsed laser utilizing broad bandwidth laser glass

    DOE Patents [OSTI]

    Payne, S.A.; Hayden, J.S.

    1997-09-02T23:59:59.000Z

    An ultrafast laser uses a Nd-doped phosphate laser glass characterized by a particularly broad emission bandwidth to generate the shortest possible output pulses. The laser glass is composed primarily of P{sub 2}O{sub 5}, Al{sub 2}O{sub 3} and MgO, and possesses physical and thermal properties that are compatible with standard melting and manufacturing methods. The broad bandwidth laser glass can be used in modelocked oscillators as well as in amplifier modules. 7 figs.

  3. Ultrafast Spectroscopy of Warm Dense Matter

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

    a plasma. Therefore, to probe a warm dense state undergoing a nonreversible process, an ultrafast technique faster than the ALS pulse duration (70 ps) and a single-shot...

  4. Ultrafast Optical Pulses: Synthesis and Applications

    E-Print Network [OSTI]

    Wang, Kai

    2013-12-11T23:59:59.000Z

    This dissertation is devoted to ultrafast waveform synthesis using coherent Raman sidebands with the assistance of pulse shapers based on acousto-optic programmable dispersive ?lter (AOPDF) or deformable mirror (DM). Ultrashort optical science has...

  5. High Resolution, Ultrafast SFG Vibrational Spectroscopy | EMSL

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

    240 nm-2600 nm for possible double resonance SFG measurement. The tunable femtosecond pulses from 240 nm to 15000 nm wavelength range also enable ultrafast pump-probe dynamics...

  6. An ultrafast carbon nanotube terahertz polarisation modulator

    SciTech Connect (OSTI)

    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

    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.

  7. Ultrafast infrared studies of complex ligand rearrangements in solution

    SciTech Connect (OSTI)

    Payne, Christine K.

    2003-05-31T23:59:59.000Z

    The complete description of a chemical reaction in solution depends upon an understanding of the reactive molecule as well as its interactions with the surrounding solvent molecules. Using ultrafast infrared spectroscopy it is possible to observe both the solute-solvent interactions and the rearrangement steps which determine the overall course of a chemical reaction. The topics addressed in these studies focus on reaction mechanisms which require the rearrangement of complex ligands and the spectroscopic techniques necessary for the determination of these mechanisms. Ligand rearrangement is studied by considering two different reaction mechanisms for which the rearrangement of a complex ligand constitutes the most important step of the reaction. The first system concerns the rearrangement of a cyclopentadienyl ring as the response of an organometallic complex to a loss of electron density. This mechanism, commonly referred to as ''ring slip'', is frequently cited to explain reaction mechanisms. However, the ring slipped intermediate is too short-lived to be observed using conventional methods. Using a combination of ultrafast infrared spectroscopy and electronic structure calculations it has been shown that the intermediate exists, but does not form an eighteen-electron intermediate as suggested by traditional molecular orbital models. The second example examines the initial steps of alkyne polymerization. Group 6 (Cr, Mo, W) pentacarbonyl species are generated photolytically and used to catalyze the polymerization of unsaturated hydrocarbons through a series of coordination and rearrangement steps. Observing this reaction on the femto- to millisecond timescale indicates that the initial coordination of an alkyne solvent molecule to the metal center results in a stable intermediate that does not rearrange to form the polymer precursor. This suggests that polymerization requires the dissociation of additional carbonyl ligands before rearrangement can occur. Overall, this research demonstrates the importance of examining reaction dynamics on the ultrafast timescale. In the case of both ring slip and alkyne polymerization, early time dynamics have been invaluable in understanding the exact reaction mechanisms which show important differences from previously accepted models.

  8. Ultrafast reaction dynamics in cluster ions: Simulation of the transient photoelectron spectrum of I2 Arn photodissociation

    E-Print Network [OSTI]

    Faeder, Jim

    Hamiltonian model of electronic structure with nonadiabatic molecular dynamics simulations, we calculate of the electronic structure of a manifold of states strongly coupled to the many solvent degrees of freedomUltrafast reaction dynamics in cluster ions: Simulation of the transient photoelectron spectrum

  9. Ultrafast dynamic ellipsometry of laser driven shock waves

    E-Print Network [OSTI]

    Bolme, Cynthia Anne

    2008-01-01T23:59:59.000Z

    The experimental measurement technique of ultrafast dynamic ellipsometry (UDE) was developed for measuring material motion and changes in optical properties of samples under laser driven shock loading. Ultrafast dynamic ...

  10. THE JOURNAL OF CHEMICAL PHYSICS 138, 244310 (2013) Molecular dynamics simulations for CO2 spectra. IV. Collisional line-mixing

    E-Print Network [OSTI]

    Boyer, Edmond

    2013-01-01T23:59:59.000Z

    atmosphere of Venus (about 96.5% of CO2) where the pressure is high (up to 90 bar). Similarly, narrow involving CO2 with a few for the pure gas in the infrared at high pressure12­17 and Raman Q branches.4THE JOURNAL OF CHEMICAL PHYSICS 138, 244310 (2013) Molecular dynamics simulations for CO2 spectra

  11. Broadband laser cooling of trapped atoms with ultrafast pulses

    E-Print Network [OSTI]

    Blinov, Boris

    Broadband laser cooling of trapped atoms with ultrafast pulses B. B. Blinov,* R. N. Kohn, Jr., M. J ions in an rf trap using ultrafast pulses from a mode-locked laser. The temperature of a single ion On the other hand, an ultrafast laser whose pulse is a few picoseconds long will naturally have a bandwidth

  12. Ultrafast x-rays: radiographing magnetism Project overview

    E-Print Network [OSTI]

    Haviland, David

    , head of the ultrafast magnetism group. Stanford PULSE is a worldwide renowned centre for ultrafast1 Ultrafast x-rays: radiographing magnetism Project overview The main purpose of the proposed, it is now possible to achieve x-ray pulses that are a few femtoseconds long and that are focused within

  13. The Physical Conditions in a Pre Super Star Cluster Molecular Cloud in the Antennae Galaxies

    E-Print Network [OSTI]

    Johnson, K E; Indebetouw, R; Brogan, C L; Whitmore, B C; Hibbard, J; Sheth, K; Evans, A

    2015-01-01T23:59:59.000Z

    We present an analysis of the physical conditions in an extreme molecular cloud in the Antennae merging galaxies. This cloud has properties consistant with those required to form a globular cluster. We have obtained ALMA CO and 870$\\mu$m observations of the Antennae galaxy system with $\\sim 0".5$ resolution. This cloud stands out in the data with a radius of $\\lesssim 24$~pc and mass of $>5\\times 10^6$~M$_\\odot$. The cloud appears capable of forming a globular cluster, but the lack of associated thermal radio emission indicates that star formation has not yet altered the environment. The lack of thermal radio emission places the cloud in an early stage of evolution, which we expect to be short-lived ($\\lesssim 1$~Myr) and thus rare. Given its mass and kinetic energy, for the cloud to be confined (as its appearance strongly suggests) it must be subject to an external pressure of P/$k_B \\gtrsim 10^8$~K~cm$^{-3}$ -- 10,000 times higher than typical interstellar pressure. This would support theories that high pre...

  14. Ultrafast Spectroscopy of Warm Dense Matter

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What'sis Taking Over OurThe Iron Spin TransitionProgram |FrankUltrafast Spectroscopy of WarmUltrafast

  15. Spatio-temporal mapping of ablated species in ultrafast laser-produced graphite plasmas

    SciTech Connect (OSTI)

    Al-Shboul, K. F.; Harilal, S. S.; Hassanein, A. [Center for Materials Under Extreme Environment, School of Nuclear Engineering, Purdue University, West Lafayette, Indiana 47907 (United States)

    2012-05-28T23:59:59.000Z

    We studied the spatial and temporal distributions of ionic, neutral, and molecular species generated by femtosecond laser produced plasma under varying ambient nitrogen gas pressures. Plasmas were generated by irradiating planar graphite targets using 40 fs pulses of 800 nm radiation from a Ti:Sapphire laser. The results show that in the presence of an ambient gas, the molecular species spatial extension and lifetime are directly correlated to the evolution of excited ions. The present studies also provide valuable insights into the evolution history of various species and their excitation during ultrafast laser ablation.

  16. Attosecond timing the ultrafast charge-transfer process in atomic collisions

    SciTech Connect (OSTI)

    Hu, S. X. [Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, New York 14623 (United States)

    2011-04-15T23:59:59.000Z

    By solving the three-dimensional, time-dependent Schroedinger equation, we have demonstrated that the ultrafast charge-transfer process in ion-atom collisions can be mapped out with attosecond extreme uv (xuv) pulses. During the dynamic-charge transfer from the target atom to the projectile ion, the electron coherently populates the two sites of both nuclei, which can be viewed as a 'short-lived' molecular state. A probing attosecond xuv pulse can instantly unleash the delocalized electron from such a ''transient molecule,'' so that the resulting photoelectron may exhibit a ''double-slit'' interference. On the contrary, either reduced or no photoelectron interference will occur if the attosecond xuv pulse strikes well before or after the collision. Therefore, by monitoring the photoelectron interference visibility, one can precisely time the ultrafast charge-transfer process in atomic collisions with time-delayed attosecond xuv pulses.

  17. PURDUE UNIVERSITY ULTRAFAST OPTICS AND OPTICAL FIBER COMMUNICATIONS LABORATORY Femtosecond Pulse

    E-Print Network [OSTI]

    Purdue University

    as new pulse sequence processing functionalities. #12;PURDUE UNIVERSITY ULTRAFAST OPTICS AND OPTICAL UNIVERSITY ULTRAFAST OPTICS AND OPTICAL FIBER COMMUNICATIONS LABORATORY CLEO 2002 One Guide ­ One PulsePURDUE UNIVERSITY ULTRAFAST OPTICS AND OPTICAL FIBER COMMUNICATIONS LABORATORY CLEO 2002

  18. Adaptive feedback control of ultrafast semiconductor nonlinearities J. Kunde,a)

    E-Print Network [OSTI]

    Keller, Ursula

    that adaptive feedback optical pulse shaping can be used to control ultrafast semiconductor nonlinearities insight into the interaction of semiconduc- tors and ultrafast optical pulses. Specifically, we develop spectroscopy. More- over, the optimized pulse shape can substantially enhance ultrafast semiconductor

  19. PURDUE UNIVERSITY ULTRAFAST OPTICS & OPTICAL FIBER COMMUNICATIONS LABORATORY Photonic RF Waveform Synthesis,

    E-Print Network [OSTI]

    Purdue University

    PURDUE UNIVERSITY ULTRAFAST OPTICS & OPTICAL FIBER COMMUNICATIONS LABORATORY Photonic RF Waveform, Shijun Xiao Funding from ARO, DARPA, and NSF #12;PURDUE UNIVERSITY ULTRAFAST OPTICS & OPTICAL FIBER performance (spectral engineering, dispersion compensation) #12;PURDUE UNIVERSITY ULTRAFAST OPTICS & OPTICAL

  20. Ultrafast Control of Magnetism in Ferromagnetic Semiconductors via Photoexcited Transient Carriers

    E-Print Network [OSTI]

    Cotoros, Ingrid A.

    2009-01-01T23:59:59.000Z

    Magneto-Optics in Nickel: Magnetism or Optics? ” Phys. Rev.Ultrafast Control of Magnetism in FerromagneticFall 2008 Ultrafast Control of Magnetism in Ferromagnetic

  1. Ultrafast Excited-State Dynamics in the Green Fluorescent Protein Variant S65T/ H148D. 1. Mutagenesis and Structural Studies,

    E-Print Network [OSTI]

    Boxer, Steven G.

    Articles Ultrafast Excited-State Dynamics in the Green Fluorescent Protein Variant S65T/ H148D. 1 Kanchanawong,# William Childs,# Steven G. Boxer,# and S. James Remington*,§ Institute of Molecular Biology chromophores, respectively. Excitation of either band leads to green emission. In wt-GFP, excitation of band

  2. PHYSICAL REVIEW B 83, 115419 (2011) Surface reconstruction transition of metals induced by molecular adsorption

    E-Print Network [OSTI]

    Gao, Hongjun

    2011-01-01T23:59:59.000Z

    by molecular adsorption J. T. Sun,1 L. Gao,1 X. B. He,1 Z. H. Cheng,1 Z. T. Deng,1 X. Lin,1 H. Hu,1 S. X. Du,1

  3. Applied Statistical Physics Molecular Engineering Conference Puerto Vallarta, Mexico, 24-29 August 2003

    E-Print Network [OSTI]

    Barbosa, Marcia C. B.

    Molecular, Instituto Mexicano del Petroleo, Eje Central Lazaro Cardenas No. 152Colonia San Bartolo Atepehuacan C.P. 07730 Mexico City 2 Instituto de Fisica, UFRGS, Caixa Postal 15051- 91501-970, Porto Alegre

  4. Suppression of Magnetic State Decoherence Using Ultrafast Optical Pulses

    E-Print Network [OSTI]

    C. Search; P. R. Berman

    2000-03-01T23:59:59.000Z

    It is shown that the magnetic state decoherence produced by collisions in a thermal vapor can be suppressed by the application of a train of ultrafast optical pulses.

  5. Ultrafast charge localization in a stripe-phase nickelate

    E-Print Network [OSTI]

    Coslovich, Giacomo

    2013-01-01T23:59:59.000Z

    21 . The ability of ultrafast optical pulses to suppress theultrafast response of the mid-IR conductivity to femtosecond optical excitation. Pump pulses

  6. Probing Ultrafast Solvation Dynamics with High Repetition-Rate...

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

    Ultrafast X-Ray Spectroscopy as a Probe of Nonequilibrium Dynamics in Ruthenium Complexes The Electronic Origin of Photoinduced Strain Modifying Proteins to Combat Disease Higher...

  7. Advanced Imaging and Ultra-fast Material Probing With Inverse...

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

    Imaging and Ultra-fast Material Probing With Inverse Compton Scattering A proposal to the Brookhaven Accelerator Test Facility Gerard Andonian, Alberto Bacci, Ubaldo...

  8. Ultrafast Structural Dynamics in Combustion Relevant Model Systems

    SciTech Connect (OSTI)

    Weber, Peter M. [Brown University

    2014-03-31T23:59:59.000Z

    The research project explored the time resolved structural dynamics of important model reaction system using an array of novel methods that were developed specifically for this purpose. They include time resolved electron diffraction, time resolved relativistic electron diffraction, and time resolved Rydberg fingerprint spectroscopy. Toward the end of the funding period, we also developed time-resolved x-ray diffraction, which uses ultrafast x-ray pulses at LCLS. Those experiments are just now blossoming, as the funding period expired. In the following, the time resolved Rydberg Fingerprint Spectroscopy is discussed in some detail, as it has been a very productive method. The binding energy of an electron in a Rydberg state, that is, the energy difference between the Rydberg level and the ground state of the molecular ion, has been found to be a uniquely powerful tool to characterize the molecular structure. To rationalize the structure sensitivity we invoke a picture from electron diffraction: when it passes the molecular ion core, the Rydberg electron experiences a phase shift compared to an electron in a hydrogen atom. This phase shift requires an adjustment of the binding energy of the electron, which is measurable. As in electron diffraction, the phase shift depends on the molecular, geometrical structure, so that a measurement of the electron binding energy can be interpreted as a measurement of the molecule’s structure. Building on this insight, we have developed a structurally sensitive spectroscopy: the molecule is first elevated to the Rydberg state, and the binding energy is then measured using photoelectron spectroscopy. The molecule’s structure is read out as the binding energy spectrum. Since the photoionization can be done with ultrafast laser pulses, the technique is inherently capable of a time resolution in the femtosecond regime. For the purpose of identifying the structures of molecules during chemical reactions, and for the analysis of molecular species in the hot environments of combustion processes, there are several features that make the Rydberg ionization spectroscopy uniquely useful. First, the Rydberg electron’s orbit is quite large and covers the entire molecule for most molecular structures of combustion interest. Secondly, the ionization does not change vibrational quantum numbers, so that even complicated and large molecules can be observed with fairly well resolved spectra. In fact, the spectroscopy is blind to vibrational excitation of the molecule. This has the interesting consequence for the study of chemical dynamics, where the molecules are invariably very energetic, that the molecular structures are observed unobstructed by the vibrational congestion that dominates other spectroscopies. This implies also that, as a tool to probe the time-dependent structural dynamics of chemically interesting molecules, Rydberg spectroscopy may well be better suited than electron or x-ray diffraction. With recent progress in calculating Rydberg binding energy spectra, we are approaching the point where the method can be evolved into a structure determination method. To implement the Rydberg ionization spectroscopy we use a molecular beam based, time-resolved pump-probe multi-photon ionization/photoelectron scheme in which a first laser pulse excites the molecule to a Rydberg state, and a probe pulse ionizes the molecule. A time-of-flight detector measures the kinetic energy spectrum of the photoelectrons. The photoelectron spectrum directly provides the binding energy of the electron, and thereby reveals the molecule’s time-dependent structural fingerprint. Only the duration of the laser pulses limits the time resolution. With a new laser system, we have now reached time resolutions better than 100 fs, although very deep UV wavelengths (down to 190 nm) have slightly longer instrument functions. The structural dynamics of molecules in Rydberg-excited states is obtained by delaying the probe ionization photon from the pump photon; the structural dynamics of molecules in their ground state or e

  9. Ultrafast Pulse Shaping Approaches to Quantum Computing

    E-Print Network [OSTI]

    Debabrata Goswami

    2003-12-24T23:59:59.000Z

    Quantum computing exploits the quantum-mechanical nature of matter to exist in multiple possible states simultaneously. This new approach promises to revolutionize the present form of computing. As an approach to quantum computing, we discuss ultrafast laser pulse shaping, in particular, the acousto-optic modulator based Fourier-Transform pulse-shaper, which has the ability to modulate tunable high power ultrafast laser pulses. We show that optical pulse shaping is an attractive route to quantum computing since shaped pulses can be transmitted over optical hardware and the same infrastructure can be used for computation and optical information transfer. We also address the problem of extending coherence-times for optically induced processes.

  10. Laser cooling with ultrafast pulse trains

    E-Print Network [OSTI]

    David Kielpinski

    2003-06-14T23:59:59.000Z

    We propose a new laser cooling method for atomic species whose level structure makes traditional laser cooling difficult. For instance, laser cooling of hydrogen requires vacuum-ultraviolet laser light, while multielectron atoms need laser light at many widely separated frequencies. These restrictions can be eased by laser cooling on two-photon transitions with ultrafast pulse trains. Laser cooling of hydrogen, antihydrogen, and carbon appears feasible, and extension of the technique to molecules may be possible.

  11. Technical Report Ultrafast X-ray Science at the Sub-Picosecond Pulse Source

    E-Print Network [OSTI]

    Wechsler, Risa H.

    1 Technical Report Ultrafast X-ray Science at the Sub-Picosecond Pulse Source Kelly J. Gaffney ultrafast phenomena. These techniques involve excitation of a sample with an ultrafast laser pump pulse, USA The ultrafast, high brightness x-ray free electron laser (XFEL) sources of the future have

  12. Controlled Coherent Excitations in a Single Cadmium Ion with an Ultrafast Laser

    E-Print Network [OSTI]

    Monroe, Christopher

    of ultrafast pulses in a Ramsey interferometer. This ultrafast coupling is vital in a scheme for generationControlled Coherent Excitations in a Single Cadmium Ion with an Ultrafast Laser by Rudolph Nicolas: Controlled Coherent Excitations in a Single Cadmium Ion with an Ultrafast Laser written by R. N. Kohn Jr. has

  13. Ultrafast X-ray Diffraction Theory Jianshu Cao* and Kent R. Wilson

    E-Print Network [OSTI]

    Cao, Jianshu

    notablely using ultrafast optical pump-probe pulses. Unfortunately, except for a few favorable cases of a sample is initiated by an ultrafast optical laser pulse and then probed by an ultrafast X-ray pulse initiated by the optical pump pulse in real time and real space.9-11 From a simple viewpoint, ultrafast X

  14. Ultrafast extended x-ray absorption fine structure ,,EXAFS...--theoretical considerations

    E-Print Network [OSTI]

    Cao, Jianshu

    13­20 to generate ultrafast x-ray pulses, however, the prospect of ultrafast EXAFS seems encouragingUltrafast extended x-ray absorption fine structure ,,EXAFS...--theoretical considerations Frank L by the recent experimental demonstration of ultrafast x-ray absorption spectroscopy, we present a framework

  15. DIRECT SPACE-TO-TIME PULSE SHAPING FOR ULTRAFAST OPTICAL

    E-Print Network [OSTI]

    Purdue University

    DIRECT SPACE-TO-TIME PULSE SHAPING FOR ULTRAFAST OPTICAL WAVEFORM GENERATION A Thesis Submitted ago. To the students, past and present, post-docs, and visitors of the Ultrafast Optics & Optical me what it is that I love about this work. The experimental optical pulse train generation devices

  16. Ultrafast lasers in the femtosecond regime: generation, amplification

    E-Print Network [OSTI]

    Ultrafast lasers in the femtosecond regime: generation, amplification and measurement Pedro can be explored. Ultrafast elec- tromagnetic fields are one of those tools, as they allow the probing is divided in two parts one that deals with the generation and amplification of ultrashort pulses the second

  17. Information processing with longitudinal spectral decomposition of ultrafast pulses

    E-Print Network [OSTI]

    Fainman, Yeshaiahu

    Information processing with longitudinal spectral decomposition of ultrafast pulses Robert E of waveforms depending on whether their frequency response is or is not known a priori. Ultrafast pulses prove synthesis and detection relying on longitudinal spectral decomposition of subpicosecond optical pulses

  18. Ultrafast electron beam imaging of femtosecond laser-induced plasma Junjie Li, Xuan Wang, Zhaoyang Chen, Richard Clinite, Samuel S. Mao et al.

    E-Print Network [OSTI]

    Cao, Jianming

    , Beijing 100190, China and Department of Physics, Shanghai Jiao Tong University, Shanghai 200240, China in the early stage of laser ablation of a copper target are investigated in real time by making ultrafast have been a subject of intensive investigation in recent years ow- ing to its importance in a wide

  19. Femtosecond laser studies of ultrafast intramolecular processes

    SciTech Connect (OSTI)

    Hayden, C. [Sandia National Laboratories, Livermore, CA (United States)

    1993-12-01T23:59:59.000Z

    The goal of this research is to better understand the detailed mechanisms of chemical reactions by observing, directly in time, the dynamics of fundamental chemical processes. In this work femtosecond laser pulses are used to initiate chemical processes and follow the progress of these processes in time. The authors are currently studying ultrafast internal conversion and subsequent intramolecular relaxation in unsaturated hydrocarbons. In addition, the authors are developing nonlinear optical techniques to prepare and monitor the time evolution of specific vibrational motions in ground electronic state molecules.

  20. Ultrafast Laser Facility | Photosynthetic Antenna Research Center

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What'sis Taking Over OurThe Iron Spin TransitionProgram |Frank CasellaEnergyUltracoldConnectUltrafast

  1. Ultrafast Spectroscopy of Warm Dense Matter

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What'sis Taking Over OurThe Iron Spin TransitionProgram |FrankUltrafast Spectroscopy of Warm Dense Matter

  2. Ultrafast Spectroscopy of Warm Dense Matter

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What'sis Taking Over OurThe Iron Spin TransitionProgram |FrankUltrafast Spectroscopy of Warm Dense

  3. Ultrafast Spectroscopy of Warm Dense Matter

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What'sis Taking Over OurThe Iron Spin TransitionProgram |FrankUltrafast Spectroscopy of Warm

  4. Ultrafast Spectroscopy of Warm Dense Matter

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of ScienceandMesa del SolStrengthening aTurbulence may bedieselsummerFact SheetsUltrafastSpectroscopy of

  5. Electron-nuclear correlations for photo-induced dynamics in molecular dimers

    E-Print Network [OSTI]

    January 2004; accepted 11 March 2004 Ultrafast photoinduced dynamics of electronic excitation in molecularElectron-nuclear correlations for photo-induced dynamics in molecular dimers Dmitri S. Kilin, Yuri dimers is drastically affected by the dynamic reorganization of inter- and intra- molecular nuclear

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

    E-Print Network [OSTI]

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

    2006-01-01T23:59:59.000Z

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

  7. Techniques for synchronization of X-Ray pulses to the pump laser in an ultrafast X-Ray facility

    E-Print Network [OSTI]

    Corlett, J.N.; Doolittle, L.; Schoenlein, R.; Staples, J.; Wilcox, R.; Zholents, A.

    2003-01-01T23:59:59.000Z

    synchronization of ultrafast x-ray pulses produced in theAccurate timing of ultrafast x-ray probe pulses emitted fromOF X-RAY PULSES TO THE PUMP LASER IN AN ULTRAFAST X-RAY

  8. Synchronization of x-ray pulses to the pump laser in an ultrafast x-ray facility

    E-Print Network [OSTI]

    Corlett, J.N.; Barry, W.; Byrd, J.M.; Schoenlein, R.; Zholents, A.

    2002-01-01T23:59:59.000Z

    Accurate timing of ultrafast x-ray probe pulses emitted fromOF X-RAY PULSES TO THE PUMP LASER IN AN ULTRAFAST X-RAY

  9. Controlling ultrafast currents by the non-linear photogalvanic effect

    E-Print Network [OSTI]

    Wachter, Georg; Lemell, Christoph; Tong, Xiao-Min; Yabana, Kazuhiro; Burgdörfer, Joachim

    2015-01-01T23:59:59.000Z

    We theoretically investigate the effect of broken inversion symmetry on the generation and control of ultrafast currents in a transparent dielectric (SiO2) by strong femto-second optical laser pulses. Ab-initio simulations based on time-dependent density functional theory predict ultrafast DC currents that can be viewed as a non-linear photogalvanic effect. Most surprisingly, the direction of the current undergoes a sudden reversal above a critical threshold value of laser intensity I_c ~ 3.8*10^13 W/cm2. We trace this switching to the transition from non-linear polarization currents to the tunneling excitation regime. We demonstrate control of the ultrafast currents by the time delay between two laser pulses. We find the ultrafast current control by the non-linear photogalvanic effect to be remarkably robust and insensitive to laser-pulse shape and carrier-envelope phase.

  10. Space charge effects in ultrafast electron diffraction and imaging

    SciTech Connect (OSTI)

    Tao Zhensheng; Zhang He; Duxbury, P. M.; Berz, Martin; Ruan, Chong-Yu [Physics and Astronomy Department, Michigan State University, East Lansing, Michigan 48824-2320 (United States)

    2012-02-15T23:59:59.000Z

    Understanding space charge effects is central for the development of high-brightness ultrafast electron diffraction and microscopy techniques for imaging material transformation with atomic scale detail at the fs to ps timescales. We present methods and results for direct ultrafast photoelectron beam characterization employing a shadow projection imaging technique to investigate the generation of ultrafast, non-uniform, intense photoelectron pulses in a dc photo-gun geometry. Combined with N-particle simulations and an analytical Gaussian model, we elucidate three essential space-charge-led features: the pulse lengthening following a power-law scaling, the broadening of the initial energy distribution, and the virtual cathode threshold. The impacts of these space charge effects on the performance of the next generation high-brightness ultrafast electron diffraction and imaging systems are evaluated.

  11. Apparatus and method for characterizing ultrafast polarization varying optical pulses

    DOE Patents [OSTI]

    Smirl, Arthur (1020 Cherry La. Northwest, Iowa City, IA 52240); Trebino, Rick P. (425 Mulqueeny St., Livermore, CA 94550)

    1999-08-10T23:59:59.000Z

    Practical techniques are described for characterizing ultrafast potentially ultraweak, ultrashort optical pulses. The techniques are particularly suited to the measurement of signals from nonlinear optical materials characterization experiments, whose signals are generally too weak for full characterization using conventional techniques.

  12. High-performance laser processing using manipulated ultrafast laser pulses

    SciTech Connect (OSTI)

    Sugioka, Koji; Cheng Ya; Xu Zhizhan; Hanada, Yasutaka; Midorikawa, Katsumi [RIKEN - Advanced Science Institute, Wako, Saitama 351-0198 (Japan); State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences (China); RIKEN - Advanced Science Institute, Wako, Saitama 351-0198 (Japan)

    2012-07-30T23:59:59.000Z

    We employ manipulated ultrafast laser pulses to realize microprocessing with high-performance. Efficient microwelding of glass substrates by irradiation by a double-pulse train of ultrafast laser pulses is demonstrated. The bonding strength of two photostructurable glass substrates welded by double-pulse irradiation was evaluated to be 22.9 MPa, which is approximately 22% greater than that of a sample prepared by conventional irradiation by a single pulse train. Additionally, the fabrication of hollow microfluidic channels with a circular cross-sectional shape embedded in fused silica is realized by spatiotemporally focusing the ultrafast laser beam. We show both theoretically and experimentally that the spatiotemporal focusing of ultrafast laser beam allows for the creation of a three-dimensionally symmetric spherical peak intensity distribution at the focal spot.

  13. Controlling ultrafast currents by the non-linear photogalvanic effect

    E-Print Network [OSTI]

    Georg Wachter; Shunsuke A. Sato; Christoph Lemell; Xiao-Min Tong; Kazuhiro Yabana; Joachim Burgdörfer

    2015-03-20T23:59:59.000Z

    We theoretically investigate the effect of broken inversion symmetry on the generation and control of ultrafast currents in a transparent dielectric (SiO2) by strong femto-second optical laser pulses. Ab-initio simulations based on time-dependent density functional theory predict ultrafast DC currents that can be viewed as a non-linear photogalvanic effect. Most surprisingly, the direction of the current undergoes a sudden reversal above a critical threshold value of laser intensity I_c ~ 3.8*10^13 W/cm2. We trace this switching to the transition from non-linear polarization currents to the tunneling excitation regime. We demonstrate control of the ultrafast currents by the time delay between two laser pulses. We find the ultrafast current control by the non-linear photogalvanic effect to be remarkably robust and insensitive to laser-pulse shape and carrier-envelope phase.

  14. Ultrafast pump-probe force microscopy with nanoscale resolution

    E-Print Network [OSTI]

    2015-01-01T23:59:59.000Z

    Cerullo, “Confocal ultrafast pump-probe spectroscopy: A newand H. J. Maris, “Time-resolved pump-probe experiments withand U. Keller, “Femtosecond pump-porbe near-field optical

  15. Ultrafast nonlinear optical properties of passive and active semiconductor devices

    E-Print Network [OSTI]

    Motamedi, Ali Reza

    2011-01-01T23:59:59.000Z

    Nonlinear optical properties and ultrafast carrier dynamics of slab-coupled optical waveguide amplifiers, silicon nanowaveguides, and III-V semiconductor saturable Bragg reflectors are studied. The limits imposed by two ...

  16. Laser safety information for the Atomic, Molecular and Optical (AMO) Physics Labs at Lehigh University modified from the laser safety program developed by the office of Environmental

    E-Print Network [OSTI]

    Huennekens, John

    1 Laser safety information for the Atomic, Molecular and Optical (AMO) Physics Labs at Lehigh University modified from the laser safety program developed by the office of Environmental Health and Safety using the following reference materials: I. American National Standards for Safe Use of Lasers - ANSI Z

  17. The ALS X-Ray Streak Camera: Bringing the Ultrafast and Ultrasmall...

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

    ultrafast is at the frontier of scientific research. Two x-ray approaches can be used for ultrafast examinations. The first entails developing sources that have short x-ray pulses...

  18. Ultrafast imaging of complex systems in 3-D at near atomic resolution...

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

    on ultrafast timescales using extremely intense X-ray free-electron laser (XFEL) pulses. One important step toward ultrafast imaging of samples with a single X-ray shot is...

  19. Ultrafast optical pulse manipulation in three dimensional-resolved microscope imaging and microfabrication

    E-Print Network [OSTI]

    Kim, Daekeun, Ph. D. Massachusetts Institute of Technology

    2009-01-01T23:59:59.000Z

    The availability of lasers with femtosecond, ultrafast light pulses provides new opportunities and challenges in instrument design. This thesis addresses three aspects of utilizing ultrafast light pulses in two-photon ...

  20. Ultrafast Optics and Optical Fiber Communications Laboratory http://purcell.ecn.purdue.edu/~fsoptics/

    E-Print Network [OSTI]

    Purdue University

    Ultrafast Optics and Optical Fiber Communications Laboratory http, A. M. Weiner Purdue University C. Lin Avanex Corporation Conference on Lasers and Electro Optics;Ultrafast Optics and Optical Fiber Communications Laboratory http://purcell.ecn.purdue.edu/~fsoptics/ 2

  1. Investigation on properties of ultrafast switching in a bulk gallium arsenide avalanche semiconductor switch

    SciTech Connect (OSTI)

    Hu, Long, E-mail: hulong-1226@126.com [Key Laboratory for Physical Electronics and Devices of the Ministry of Education, Xi'an Jiaotong University, Xi'an 710049 (China); Science and Technology on High Power Microwave Laboratory, Northwest Institute of Nuclear Technology, Xi'an 710024 (China); Su, Jiancang; Ding, Zhenjie; Hao, Qingsong; Yuan, Xuelin [Science and Technology on High Power Microwave Laboratory, Northwest Institute of Nuclear Technology, Xi'an 710024 (China)

    2014-03-07T23:59:59.000Z

    Properties of ultrafast switching in a bulk gallium arsenide (GaAs) avalanche semiconductor switch based on semi-insulating wafer, triggered by an optical pulse, were analyzed using physics-based numerical simulations. It has been demonstrated that when a voltage with amplitude of 5.2?kV is applied, after an exciting optical pulse with energy of 1??J arrival, the structure with thickness of 650??m reaches a high conductivity state within 110 ps. Carriers are created due to photons absorption, and electrons and holes drift to anode and cathode terminals, respectively. Static ionizing domains appear both at anode and cathode terminals, and create impact-generated carriers which contribute to the formation of electron-hole plasma along entire channel. When the electric field in plasma region increases above the critical value (?4?kV/cm) at which the electrons drift velocity peaks, a domain comes into being. An increase in carrier concentration due to avalanche multiplication in the domains reduces the domain width and results in the formation of an additional domain as soon as the field outside the domains increases above ?4?kV/cm. The formation and evolution of multiple powerfully avalanching domains observed in the simulations are the physical reasons of ultrafast switching. The switch exhibits delayed breakdown with the characteristics affected by biased electric field, current density, and optical pulse energy. The dependence of threshold energy of the exciting optical pulse on the biased electric field is discussed.

  2. A grazing incidence x-ray streak camera for ultrafast, single-shot measurements

    E-Print Network [OSTI]

    Feng, Jun

    2010-01-01T23:59:59.000Z

    provided by UV pulses derived from an ultrafast laser. Dueultrafast dynamics using a single synchrotron x-ray pulse.

  3. Plasmonic Near-Electric Field Enhancement Effects in Ultrafast Photoelectron Emission: Correlated Spatial and Laser Polarization

    E-Print Network [OSTI]

    Mohseni, Hooman

    ABSTRACT: Electron emission from single, supported Ag nanocubes excited with ultrafast laser pulses ( = 800 irradiated with ultrafast laser pulses at a photon energy (Eph) below the material work functionPlasmonic Near-Electric Field Enhancement Effects in Ultrafast Photoelectron Emission: Correlated

  4. ULTRAFAST OPTICS AND OPTICAL FIBER COMMUNICATIONS LABORATORYLEOS 2003 Multiple Output Channel

    E-Print Network [OSTI]

    Purdue University

    DSTAWG DST Pulse Shaper Fiber ports Imaging optics U.S. Quarter #12;ULTRAFAST OPTICS AND OPTICAL FIBER;ULTRAFAST OPTICS AND OPTICAL FIBER COMMUNICATIONS LABORATORYLEOS 2003 One Guide ­ One Pulse Pulses slab Loss-engineering to control relative pulse amplitude. #12;ULTRAFAST OPTICS AND OPTICAL FIBER

  5. Optical coherence and beamspread in ultrafast-laser pulsetrain-burst hole drilling

    E-Print Network [OSTI]

    Marjoribanks, Robin S.

    advantages over single-pulse laser processing of materials and biological tissues. Ultrafast lasers are often material, as is sometimes the case for nanosecond-pulse ablation; further, pulsetrain-bursts of ultrafast of ultrafast laser pulses, at a repetition rate of 1 MHz or greater, is less likely to leave cracks or residual

  6. Title of dissertation: ULTRAFAST CONTROL OF SPIN AND MOTION IN TRAPPED IONS

    E-Print Network [OSTI]

    Monroe, Christopher

    , I report here on the first experiments using ultrafast laser pulses to control the internalABSTRACT Title of dissertation: ULTRAFAST CONTROL OF SPIN AND MOTION IN TRAPPED IONS Jonathan and external states of a single trapped ion. I begin with experiments in ultrafast spin control, showing how

  7. Proceedings of SPIE, Vol. 5825, 118-138 (2005) Ultrafast coherent spectroscopy of single semiconductor

    E-Print Network [OSTI]

    Peinke, Joachim

    ultrafast optical pulses to probe and control coherent polarizations. In this article, we review our recentProceedings of SPIE, Vol. 5825, 118-138 (2005) Ultrafast coherent spectroscopy of single work on combining ultrafast spectroscopy and near-field microscopy to probe the nonlinear optical

  8. Characterization of a liquid-crystal ultrafast pulse shaper for ultra-broadband applications

    E-Print Network [OSTI]

    Characterization of a liquid-crystal ultrafast pulse shaper for ultra-broadband applications pulse shaping Spatial light modulators Ultrafast optics Femtosecond pulses a b s t r a c t By combining in revised form 22 January 2014 Accepted 28 January 2014 Available online 6 February 2014 Keywords: Ultrafast

  9. Single pulse ultrafast laser imprinting of axial dot arrays in bulk glasses C. Mauclair,1,

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Single pulse ultrafast laser imprinting of axial dot arrays in bulk glasses C. Mauclair,1, A sam- ples were irradiated with 160 fs pulses from an 800 nm Ti:Sapphire amplified ultrafast laser.mauclair@univ-st-etienne.fr Compiled December 20, 2010 Ultrafast laser processing of bulk transparent materials can significantly gain

  10. Breathing coherent phonons and caps fragmentation in carbon nanotubes following ultrafast laser pulses

    E-Print Network [OSTI]

    Dumitrica,Traian

    driven by ultrafast laser pulses.1­3 The necessary conditions for generating such coherent phonons are i is larger than the duration of currently available ultrafast pulses. ii Measurements4­7 determinedBreathing coherent phonons and caps fragmentation in carbon nanotubes following ultrafast laser

  11. Generation of mega-electron-volt electron beams by an ultrafast intense laser pulse

    E-Print Network [OSTI]

    Umstadter, Donald

    Generation of mega-electron-volt electron beams by an ultrafast intense laser pulse Xiaofang Wang emission from the interaction of an ultrafast ( 29 fs), intense ( 1018 W/cm2 ) laser pulse with underdense of such an ultrafast laser pulse with matter and possible new approaches to MeV electron generation. In this paper we

  12. Parametric cascade downconverter for intense ultrafast mid-infrared generation beyond the ManleyRowe

    E-Print Network [OSTI]

    Boyer, Edmond

    codes: 190.2620, 190.4970, 320.7160, 320.7110. Intense and ultrafast optical pulses (durations typ of optical sources that directly produce ultrafast intense pulses at long wavelengths. One technique that has from in- tense ultrafast pulses in the near infrared 800 nm . Recent results that produce intense

  13. Fourier information optics for the ultrafast time domain Andrew M. Weiner

    E-Print Network [OSTI]

    Purdue University

    of ultrafast pulses. These examples exploit time­ frequency Fourier techniques to perform matched filtering processing of ultrafast pulsed signals, in close analogy with the spatial Fourier techniques used by LeithFourier information optics for the ultrafast time domain Andrew M. Weiner School of Electrical

  14. Control of ultrafast electron dynamics with shaped femtosecond laser pulses: from atoms to solids

    E-Print Network [OSTI]

    Peinke, Joachim

    Control of ultrafast electron dynamics with shaped femtosecond laser pulses: from atoms to solids;1. Introduction In coherent control shaped femtosecond laser pulses are used as a tool to steer the ultrafast focus on advanced control of ultrafast electron dynamics with shaped femtosecond laser pulses

  15. Physics

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of Science (SC)IntegratedSpeeding accessPeptoidLabPhysics Physics Our science answers questions

  16. Physics

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of Science (SC)IntegratedSpeeding accessPeptoidLabPhysics Physics Our science answers

  17. Ultrafast energy transfer from rigid, branched side-chains into a conjugated, alternating copolymer

    SciTech Connect (OSTI)

    Griffin, Graham B.; Rolczynski, Brian S.; Linkin, Alexander; McGillicuddy, Ryan D.; Engel, Gregory S., E-mail: gsengel@uchicago.edu [Department of Chemistry, The James Franck Institute, Institute for Biophysical Dynamics, The University of Chicago, Chicago, Illinois 60637 (United States); Lundin, Pamela M. [Department of Chemical Engineering, Stanford University, Stauffer III, 381 North-South Mall, Stanford, California 94305 (United States) [Department of Chemical Engineering, Stanford University, Stauffer III, 381 North-South Mall, Stanford, California 94305 (United States); A. R. Smith Department of Chemistry, Appalachian State University, 417 CAP Building, 525 Rivers Street, Boone, North Carolina 28608 (United States); Bao, Zhenan [Department of Chemical Engineering, Stanford University, Stauffer III, 381 North-South Mall, Stanford, California 94305 (United States)] [Department of Chemical Engineering, Stanford University, Stauffer III, 381 North-South Mall, Stanford, California 94305 (United States)

    2014-01-21T23:59:59.000Z

    We present the synthesis and characterization of a benzodithiophene/thiophene alternating copolymer decorated with rigid, singly branched pendant side chains. We characterize exciton migration and recombination dynamics in these molecules in tetrahydrofuran solution, using a combination of static and time-resolved spectroscopies. As control experiments, we also measure electronic relaxation dynamics in isolated molecular analogues of both the side chain and polymer moieties. We employ semi-empirical and time-dependent density functional theory calculations to show that photoexcitation of the decorated copolymer using 395 nm laser pulses results in excited states primarily localized on the pendant side chains. We use ultrafast transient absorption spectroscopy to show that excitations are transferred to the polymer backbone faster than the instrumental response function, ?250 fs.

  18. Ultrafast optical spin echo for electron spins in semiconductors

    E-Print Network [OSTI]

    Susan M. Clark; Kai-Mei C. Fu; Qiang Zhang; Thaddeus D. Ladd; Colin Stanley; Yoshihisa Yamamoto

    2009-04-03T23:59:59.000Z

    Spin-based quantum computing and magnetic resonance techniques rely on the ability to measure the coherence time, T2, of a spin system. We report on the experimental implementation of all-optical spin echo to determine the T2 time of a semiconductor electron-spin system. We use three ultrafast optical pulses to rotate spins an arbitrary angle and measure an echo signal as the time between pulses is lengthened. Unlike previous spin-echo techniques using microwaves, ultrafast optical pulses allow clean T2 measurements of systems with dephasing times T2* fast in comparison to the timescale for microwave control. This demonstration provides a step toward ultrafast optical dynamic decoupling of spin-based qubits.

  19. Impact system for ultrafast synchrotron experiments

    SciTech Connect (OSTI)

    Jensen, B. J.; Owens, C. T.; Ramos, K. J.; Yeager, J. D.; Saavedra, R. A.; Luo, S. N.; Hooks, D. E. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Iverson, A. J. [National Security Technologies, Los Alamos, New Mexico 87544 (United States); Fezzaa, K. [Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States)

    2013-01-15T23:59:59.000Z

    The impact system for ultrafast synchrotron experiments, or IMPULSE, is a 12.6-mm bore light-gas gun (<1 km/s projectile velocity) designed specifically for performing dynamic compression experiments using the advanced imaging and X-ray diffraction methods available at synchrotron sources. The gun system, capable of reaching projectile velocities up to 1 km/s, was designed to be portable for quick insertion/removal in the experimental hutch at Sector 32 ID-B of the Advanced Photon Source (Argonne, IL) while allowing the target chamber to rotate for sample alignment with the beam. A key challenge in using the gun system to acquire dynamic data on the nanosecond time scale was synchronization (or bracketing) of the impact event with the incident X-ray pulses (80 ps width). A description of the basic gun system used in previous work is provided along with details of an improved launch initiation system designed to significantly reduce the total system time from launch initiation to impact. Experiments were performed to directly measure the gun system time and to determine the gun performance curve for projectile velocities ranging from 0.3 to 0.9 km/s. All results show an average system time of 21.6 {+-} 4.5 ms, making it possible to better synchronize the gun system and detectors to the X-ray beam.

  20. Physics

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What's Possible for RenewableSpeedingBiomassPPPOPetroleum Reserves Vision,4newsSolarrdPhysicistsPhysics

  1. Characterization of iso-CF{sub 2}I{sub 2} in frequency and ultrafast time domains

    SciTech Connect (OSTI)

    El-Khoury, Patrick Z.; Tarnovsky, Alexander N. [Department of Chemistry and Center for Photochemical Sciences, Bowling Green State University, Bowling Green, Ohio 43403-0001 (United States); George, Lisa; Kalume, Aimable; Reid, Scott A. [Department of Chemistry, Marquette University, Milwaukee, Wisconsin 53201-1881 (United States); Ault, Bruce S. [Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221-0172 (United States)

    2010-03-28T23:59:59.000Z

    The photolysis of diiododifluoromethane (CF{sub 2}I{sub 2}) in condensed phases was studied by a combination of matrix isolation and ultrafast time-resolved spectroscopy, in concert with ab initio calculations. Photolysis at wavelengths of 355 or 266 nm of CF{sub 2}I{sub 2}:Ar samples (1:5000) held at {approx}8 K yielded iso-CF{sub 2}I{sub 2} (F{sub 2}C-I-I), a metastable isomer of CF{sub 2}I{sub 2}, characterized here for the first time. The infrared (IR) spectra of this isomer were recorded in matrix experiments, and the derived positions of the C-F stretching modes are in very good agreement with the predictions of high level ab initio calculations, which show that the iso-form is a minimum on the CF{sub 2}I{sub 2} ground state potential energy surface. The formation of this isomer following 350 nm excitation of CF{sub 2}I{sub 2} in room temperature CCl{sub 4} solutions was monitored through its intense C-F stretching mode by means of ultrafast time-resolved IR absorption. Together, matrix isolation and ultrafast IR absorption experiments suggest that the formation of iso-CF{sub 2}I{sub 2} occurs via recombination of CF{sub 2}I radical and I atom. Ultrafast IR experiments detect a delayed rise of iso-CF{sub 2}I-I absorption, placing an upper limit of 400 fs for the C-I bond dissociation and primary geminate recombination processes. The product absorption spectrum recorded 1 ns after 350 nm excitation of CF{sub 2}I{sub 2} in solution is virtually identical to the visible absorption spectrum of iso-CF{sub 2}I{sub 2} trapped in matrix isolation experiments [with subtracted I{sub 2}(X) absorption]. The formation of this isomer in solution at room temperature has direct dynamic implications for the ultrafast production of molecular iodine from electronically excited CF{sub 2}I{sub 2}.

  2. Ultrafast dynamic ellipsometry and spectroscopy of laser shocked materials

    SciTech Connect (OSTI)

    Bolme, Cynthia A [Los Alamos National Laboratory; Mc Grane, Shawn D [Los Alamos National Laboratory; Dang, Nhan C [Los Alamos National Laboratory; Whitley, Von H [Los Alamos National Laboratory; Moore, David S. [Los Alamos National Laboratory

    2011-01-20T23:59:59.000Z

    Ultrafast dynamic ellipsometry is used to measure the material motion and changes in the optical refractive index of laser shock compressed materials. This diagnostic has shown us that the ultrafast laser driven shocks are the same as shocks on longer timescales and larger length scales. We have added spectroscopic diagnostics of infrared absorption, ultra-violet - visible transient absorption, and femtosecond stimulated Raman scattering to begin probing the initiation chemistry that occurs in shock reactive materials. We have also used the femtosecond stimulated Raman scattering to measure the vibrational temperature of materials using the Stokes gain to anti-Stokes loss ratio.

  3. Ultrafast reduction of the total magnetization in iron

    SciTech Connect (OSTI)

    Fognini, A., E-mail: afognini@phys.ethz.ch; Michlmayr, T. U.; Salvatella, G.; Vaterlaus, A.; Acremann, Y., E-mail: acremann@solid.phys.ethz.ch [Laboratory for Solid State Physics, Otto-Stern-Weg 1, ETH Zurich, 8093 Zurich (Switzerland); Wetli, C. [Multifunktionale Ferroische Mat., Vladimir-Prelog-Weg 1-5/10, ETH Zurich, 8093 Zurich (Switzerland); Ramsperger, U.; Bähler, T.; Pescia, D. [Laboratory for Solid State Physics, Auguste-Piccard-Hof 1, ETH Zurich, 8093 Zurich (Switzerland); Sorgenfrei, F.; Beye, M.; Eschenlohr, A.; Pontius, N.; Föhlisch, A. [Institut für Methoden und Instrumentierung der Forschung mit Synchrotronstrahlung, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, 12489 Berlin (Germany); Stamm, C. [Institut für Methoden und Instrumentierung der Forschung mit Synchrotronstrahlung, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, 12489 Berlin (Germany); Department of Materials, ETH Zurich, Hönggerbergring 64, 8093 Zurich (Switzerland); Hieke, F.; Dell'Angela, M.; Wurth, W. [Institut für Experimentalphysik and Center for Free-Electron Laser Science, Universität Hamburg, 22607 Hamburg (Germany); Jong, S. de; Dürr, H. A. [SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); and others

    2014-01-20T23:59:59.000Z

    Surprisingly, if a ferromagnet is exposed to an ultrafast laser pulse, its apparent magnetization is reduced within less than a picosecond. Up to now, the total magnetization, i.e., the average spin polarization of the whole valence band, was not detectable on a sub-picosecond time scale. Here, we present experimental data, confirming the ultrafast reduction of the total magnetization. Soft x-ray pulses from the free electron laser in Hamburg (FLASH) extract polarized cascade photoelectrons from an iron layer excited by a femtosecond laser pulse. The spin polarization of the emitted electrons is detected by a Mott spin polarimeter.

  4. Attosecond X-Ray Pulses for Molecular Electronic Dynamics

    E-Print Network [OSTI]

    Abel, Mark Joseph

    2010-01-01T23:59:59.000Z

    techniques for ultrafast laser pulse characterization. Thethe ultrafast evolution of the driver pulse intensity, weisolated pulse production will enable probing of ultrafast

  5. Towards simultaneous measurements of electronic and structural properties in ultra-fast x-ray free electron laser absorption spectroscopy experiments

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

    Gaudin, J.; Fourment, C.; Cho, B. I.; Engelhorn, K.; Galtier, E.; Harmand, M.; Leguay, P. M.; Lee, H. J.; Nagler, B.; Nakatsutsumi, M.; et al

    2014-04-17T23:59:59.000Z

    The rapidly growing ultrafast science with X-ray lasers unveils atomic scale processes with unprecedented time resolution bringing the so called “molecular movie” within reach. X-ray absorption spectroscopy is one of the most powerful x-ray techniques providing both local atomic order and electronic structure when coupled with ad-hoc theory. Collecting absorption spectra within few x-ray pulses is possible only in a dispersive setup. We demonstrate ultrafast time-resolved measurements of the LIII-edge x-ray absorption near-edge spectra of irreversibly laser excited Molybdenum using an average of only few x-ray pulses with a signal to noise ratio limited only by the saturation level ofmore »the detector. The simplicity of the experimental set-up makes this technique versatile and applicable for a wide range of pump-probe experiments, particularly in the case of non-reversible processes.« less

  6. PURDUE UNIVERSITY ULTRAFAST OPTICS & OPTICAL FIBER COMMUNICATIONS LABORATORYA.M. Weiner Andrew M. Weiner, Jason McKinney*, and Shijun Xiao

    E-Print Network [OSTI]

    Purdue University

    PURDUE UNIVERSITY ULTRAFAST OPTICS & OPTICAL FIBER COMMUNICATIONS LABORATORYA.M. Weiner Andrew M affiliation: Naval Research Labs #12;PURDUE UNIVERSITY ULTRAFAST OPTICS & OPTICAL FIBER COMMUNICATIONS bandwidth #12;PURDUE UNIVERSITY ULTRAFAST OPTICS & OPTICAL FIBER COMMUNICATIONS LABORATORYA.M. Weiner

  7. LCLS Ultrafast Science Instruments:Conceptual Design Report

    SciTech Connect (OSTI)

    Arthur, J.; Boutet, S.; Castagna, J-C.; Chapman, H.; Feng, Y.; Foyt, W.; Fritz, D.M.; Gaffney, K.J.; Gr|bel, G.; Hajdu, J.; Hastings, J.B.; Kurita, N.; Larsson, J.; Ludwig, K.; Messerschmidt, M.; Miao, J.; Reis, D.A.; Robert, A.; Stephenson, G.B.; Tschentscher, Th.; van Bakel, N.; /SLAC /LLNL, Livermore /DESY /Lund Inst. Tech. /Boston U. /UCLA /Michigan U. /Argonne

    2007-10-16T23:59:59.000Z

    The Stanford Linear Accelerator Center (SLAC), along with Argonne National Laboratory (ANL), Lawrence Livermore National Laboratory (LLNL), and the University of California at Los Angeles (UCLA), is constructing a Free-Electron Laser (FEL) facility, which will operate in the wavelength range 1.5 nm - 0.15 nm. This FEL, the Linac Coherent Light Source (LCLS), utilizes the SLAC linac and will produce sub-picosecond pulses of short wavelength X-rays with very high peak brightness and almost complete transverse coherence. The final one-third of the SLAC linac will be used as the source of electrons for the LCLS. The high energy electrons will be transported across the SLAC Research Yard, into a tunnel which will house a long undulator. In passing through the undulator, the electrons will be bunched by the force of their own synchrotron radiation and produce an intense, monochromatic, spatially coherent beam of X-rays. By varying the electron energy, the FEL X-ray wavelength will be tunable from 1.5 nm to 0.15 nm. The LCLS will include two experimental halls as well as X-ray optics and infrastructure necessary to create a facility that can be developed for research in a variety of disciplines such as atomic physics, materials science, plasma physics and biosciences. This Conceptual Design Report, the authors believe, confirms the feasibility of designing and constructing three X-ray instruments in order to exploit the unique scientific capability of this new LCLS facility. The technical objective of the LCLS Ultrafast Science Instruments (LUSI) project is to design, build, and install at the LCLS three hard X-ray instruments that will complement the initial instrument included in the LCLS construction. As the science programs advance and new technological challenges appear, instrumentation needs to be developed and ready to conquer these new opportunities. The LCLS instrument concepts have been developed in close consultation with the scientific community through a series of workshops team meetings and focused reviews. In particular, the LUSI project instruments have been identified as meeting the most urgent needs of the scientific community based on the advice of the LCLS Scientific Advisory Committee (SAC) in response to an open call for letters of intent (LOI) from the breadth of the scientific community.

  8. 5D Data Storage by Ultrafast Laser Nanostructuring in Glass

    E-Print Network [OSTI]

    Anderson, Jim

    5D Data Storage by Ultrafast Laser Nanostructuring in Glass Jingyu Zhang* , Mindaugas Gecevicius-assembled form birefringence and retrieved in glass opening the era of unlimited lifetime data storage. © 2013 laser writing in glass were proposed for the polarization multiplexed optical memory, where

  9. Apparatus and method for characterizing ultrafast polarization varying optical pulses

    DOE Patents [OSTI]

    Smirl, A.; Trebino, R.P.

    1999-08-10T23:59:59.000Z

    Practical techniques are described for characterizing ultrafast potentially ultraweak, ultrashort optical pulses. The techniques are particularly suited to the measurement of signals from nonlinear optical materials characterization experiments, whose signals are generally too weak for full characterization using conventional techniques. 2 figs.

  10. Unraveling shock-induced chemistry using ultrafast lasers

    SciTech Connect (OSTI)

    Moore, David Steven [Los Alamos National Laboratory

    2010-12-06T23:59:59.000Z

    The exquisite time synchronicity between shock and diagnostics needed to unravel chemical events occurring in picoseconds has been achieved using a shaped ultrafast laser pulse to both drive the shocks and interrogate the sample via a multiplicity of optical diagnostics. The shaped laser drive pulse can produce well-controlled shock states of sub-ns duration with sub-10 ps risetimes, sufficient for investigation offast reactions or phase transformations in a thin layer with picosecond time resolution. The shock state is characterized using ultrafast dynamic ellipsometry (UDE) in either planar or Gaussian spatial geometries, the latter allowing measurements of the equation of state of materials at a range of stresses in a single laser pulse. Time-resolved processes in materials are being interrogated using UDE, ultrafast infrared absorption, ultrafast UV/visible absorption, and femtosecond stimulated Raman spectroscopy. Using these tools we showed that chemistry in an energetic thin film starts only after an induction time of a few tens of ps, an observation that allows differentiation between proposed shock-induced reaction mechanisms. These tools are presently being applied to a variety of energetic and reactive sample systems, from nitromethane and carbon disulfide, to microengineered interfaces in tunable energetic mixtures. Recent results will be presented, and future trends outlined.

  11. Unraveling shock-induced chemistry using ultrafast lasers

    SciTech Connect (OSTI)

    Moore, David S [Los Alamos National Laboratory

    2009-01-01T23:59:59.000Z

    The exquisite time synchronicity between shock and diagnostics needed to unravel chemical events occurring in picoseconds has been achieved using a shaped ultrafast laser pulse to both drive the shocks and interrogate the sample via a multiplicity of optical diagnostics. The shaped laser drive pulse can produce well-controlled shock states of sub-ns duration with sub-10 ps risetimes, sufficient for investigation of fast reactions or phase transformations in a thin layer with picosecond time resolution. The shock state is characterized using ultrafast dynamic ellipsometry (UDE) in either planar or Gaussian spatial geometries, the latter allowing measurements of the equation of state of materials at a range of stresses in a single laser pulse. Time-resolved processes in materials are being interrogated using UDE, ultrafast infrared absorption, ultrafast UV/visible absorption, and femtosecond stimulated Raman spectroscopy. Using these tools we showed that chemistry in an energetic thin film starts only after an induction time of a few tens of ps, an observation that allows differentiation between proposed shock-induced reaction mechanisms. These tools are presently being applied to a variety of energetic and reactive sample systems, from nitromethane and carbon disulfide, to micro-engineered interfaces in tunable energetic mixtures.

  12. Science Challenge Computational modeling of ultrafast digital electronics

    E-Print Network [OSTI]

    Freericks, Jim

    properties in response to the needs of a particular device or situation. These smart electronics have the potential to lead to entirely new generations of electronic devices--such as military and civilian Science Challenge ­ Computational modeling of ultrafast digital electronics · To understand how

  13. Structural Dynamics of a Catalytic Monolayer Probed by Ultrafast

    E-Print Network [OSTI]

    Fayer, Michael D.

    REPORTS Structural Dynamics of a Catalytic Monolayer Probed by Ultrafast 2D IR Vibrational Echoes in solutions. Here, we extend the technique to probing the interfacial dynamics and structure of a silica. The structural dynamics, as reported on by a carbonyl stretch vibration of the surface-bound complex, have

  14. Snapshots of the retarded interaction of charge carriers with ultrafast fluctuations in cuprates

    E-Print Network [OSTI]

    Conte, S Dal; Golež, D; Mierzejewski, M; Soavi, G; Peli, S; Banfi, F; Ferrini, G; Comin, R; Ludbrook, B M; Chauviere, L; Zhigadlo, N D; Eisaki, H; Greven, M; Lupi, S; Damascelli, A; Brida, D; Capone, M; Bon?a, J; Cerullo, G; Giannetti, C

    2015-01-01T23:59:59.000Z

    One of the pivotal questions in the physics of high-temperature superconductors is whether the low-energy dynamics of the charge carriers is mediated by bosons with a characteristic timescale. This issue has remained elusive since electronic correlations are expected to dramatically speed up the electron-boson scattering processes, confining them to the very femtosecond timescale that is hard to access even with state-of-the-art ultrafast techniques. Here we simultaneously push the time resolution and the frequency range of transient reflectivity measurements up to an unprecedented level that enables us to directly observe the 16 fs build-up of the effective electron-boson interaction in hole-doped copper oxides. This extremely fast timescale is in agreement with numerical calculations based on the t-J model and the repulsive Hubbard model, in which the relaxation of the photo-excited charges is achieved via inelastic scattering with short-range antiferromagnetic excitations.

  15. Direct observation of ultrafast many-body electron dynamics in a strongly-correlated ultracold Rydberg gas

    E-Print Network [OSTI]

    Nobuyuki Takei; Christian Sommer; Claudiu Genes; Guido Pupillo; Haruka Goto; Kuniaki Koyasu; Hisashi Chiba; Matthias Weidemüller; Kenji Ohmori

    2015-04-14T23:59:59.000Z

    Many-body interactions govern a variety of important quantum phenomena ranging from superconductivity and magnetism in condensed matter to solvent effects in chemistry. Understanding those interactions beyond mean field is a holy grail of modern sciences. AMO physics with advanced laser technologies has recently emerged as a new platform to study quantum many-body systems. One of its latest developments is the study of long-range interactions among ultracold particles to reveal the effects of many-body correlations. Rydberg atoms distinguish themselves by their large dipole moments and tunability of dipolar interactions. Most of ultracold Rydberg experiments have been performed with narrow-band lasers in the Rydberg blockade regime. Here we demonstrate an ultracold Rydberg gas in a complementary regime, where electronic coherence is created using a broadband picosecond laser pulse, thus circumventing the Rydberg blockade to induce strong many-body correlations. The effects of long-range Rydberg interactions have been investigated by time-domain Ramsey interferometry with attosecond precision. This approach allows for the real-time observation of coherent and ultrafast many-body dynamics in which the electronic coherence is modulated by the interaction-induced correlations. The modulation evolves more rapidly than expected for two-body correlations by several orders of magnitude. We have actively controlled such ultrafast many-body dynamics by tuning the principal quantum number and the population of the Rydberg state. The observed Ramsey interferograms are well reproduced by a theoretical model beyond mean-field approximation, which can be relevant to other similar many-body phenomena in condensed matter physics and chemistry. Our new approach opens a new avenue to observe and manipulate nonequilibrium dynamics of strongly-correlated quantum many-body systems on the ultrafast timescale.

  16. Ultrafast X-Ray Spectroscopy as a Probe of Nonequilibrium Dynamics...

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

    dynamic broadenings, and changes in the branching ratio. The authors demonstrate that ultrafast x-ray spectroscopy is a suitable probe to deliver detailed new insights or...

  17. THE JOURNAL OF CHEMICAL PHYSICS 135, 184307 (2011) Characterizing molecular motion in H2O and H3O+

    E-Print Network [OSTI]

    Berry, R. Stephen

    2011-01-01T23:59:59.000Z

    instability and chaos. New approaches are necessary to fully analyze these aspects of classical molecular+ with dynamical instability statistics Jason R. Green,1 Thomas S. Hofer,2 R. Stephen Berry,3 and David J. Wales4,a-3100, USA 2 Theoretical Chemistry Division, Institute of General, Inorganic and Theoretical Chemistry

  18. INSTITUTE OF PHYSICS PUBLISHING JOURNAL OF PHYSICS B: ATOMIC, MOLECULAR AND OPTICAL PHYSICS J. Phys. B: At. Mol. Opt. Phys. 36 (2003) 41274143 PII: S0953-4075(03)64763-2

    E-Print Network [OSTI]

    Morrison, Michael A.

    in molecular gases, focusing on collisional excitation of molecularrotationaland ro conservation and the vector dynamics associated with rotational excitation. It is pointed out. In particular, for swarms of electrons or ions in molecular gases, it is clear that excitation of rotational

  19. Magnetismo Molecular (Molecular Magentism)

    SciTech Connect (OSTI)

    Reis, Mario S [Universidade Federal Fluminense, Brasil; Moreira Dos Santos, Antonio F [ORNL

    2010-07-01T23:59:59.000Z

    The new synthesis processes in chemistry open a new world of research, new and surprising materials never before found in nature can now be synthesized and, as a wonderful result, observed a series of physical phenomena never before imagined. Among these are many new materials the molecular magnets, the subject of this book and magnetic properties that are often reflections of the quantum behavior of these materials. Aside from the wonderful experience of exploring something new, the theoretical models that describe the behavior these magnetic materials are, in most cases, soluble analytically, which allows us to know in detail the physical mechanisms governing these materials. Still, the academic interest in parallel this subject, these materials have a number of properties that are promising to be used in technological devices, such as in computers quantum magnetic recording, magnetocaloric effect, spintronics and many other devices. This volume will journey through the world of molecular magnets, from the structural description of these materials to state of the art research.

  20. Comparison of 13CO Line and Far-Infrared Continuum Emission as a Diagnostic of Dust and Molecular Gas Physical Conditions: III. Systematic Effects and Scientific Implications

    E-Print Network [OSTI]

    W. F. Wall

    2007-03-26T23:59:59.000Z

    Far-infrared continuum data from the {\\it COBE}/{\\it DIRBE} instrument were combined with Nagoya 4-m $\\cOone$ spectral line data to infer the multiparsec-scale physical conditions in the Orion$ $A and B molecular clouds, using 140$\\um$/240$\\um$ dust color temperatures and the 240$\\um$/$\\cOone$ intensity ratios. In theory, the ratio of far-IR, submillimeter, or millimeter continuum to that of a $\\cO$ (or $\\Co$) rotational line can place reliable upper limits on the temperature of the dust and molecular gas on multi-parsec scales; on such scales, both the line and continuum emission are optically thin, resulting in a continuum-to-line ratio that suffers no loss of temperature sensitivity in the high-temperature limit as occurs for ratios of CO rotational lines or ratios of continuum emission in different wavelength bands. Two-component models fit the Orion data best, where one has a fixed-temperature and the other has a spatially varying temperature. The former represents gas and dust towards the surface of the clouds that are heated primarily by a very large-scale (i.e. $\\sim 1 $kpc) interstellar radiation field. The latter represents gas and dust at greater depths into the clouds and are shielded from this interstellar radiation field and heated by local stars. The inferred physical conditions are consistent with those determined from previously observed maps of $\\COone$ and $\\Jtwo$ that cover the entire Orion$ $A and B molecular clouds. The models require that the dust-gas temperature difference is 0$\\pm 2 $K. If this surprising result applies to much of the Galactic ISM, except in unusual regions such as the Galactic Center, then there are a number implications.

  1. THE JOURNAL OF CHEMICAL PHYSICS 138, 024317 (2013) Molecular dynamics simulations of diffusion and clustering along critical

    E-Print Network [OSTI]

    Firoozabadi, Abbas

    2013-01-01T23:59:59.000Z

    but is also finite at the critical point. © 2013 American Institute of Physics. [http://dx.doi.org/10. In contrast, data by Etesse et al.6 from pulsed gradient spin-echo nuclear magnetic reso- nance, where

  2. Comparison of 13CO Line and Far-Infrared Continuum Emission as a Diagnostic of Dust and Molecular Gas Physical Conditions: I. Motivation and Modeling

    E-Print Network [OSTI]

    W. F. Wall

    2006-05-25T23:59:59.000Z

    Determining temperatures in molecular clouds from ratios of CO rotational lines or from ratios of continuum emission in different wavelength bands suffers from reduced temperature sensitivity in the high-temperature limit. In theory, the ratio of far-IR, submillimeter, or millimeter continuum to that of a 13CO (or C18O) rotational line can place reliable upper limits on the temperature of the dust and molecular gas. Consequently, far-infrared continuum data from the {\\it COBE}/{\\it DIRBE} instrument and Nagoya 4-m $\\cOone$ spectral line data were used to plot 240$\\um$/13CO J=1-0 intensity ratios against 140$\\um$/240$\\um$ dust color temperatures, allowing us to constrain the multiparsec-scale physical conditions in the Orion$ $A and B molecular clouds. The best-fitting models to the Orion clouds consist of two components: a component near the surface of the clouds that is heated primarily by a very large-scale (i.e. $\\sim 1 $kpc) interstellar radiation field and a component deeper within the clouds. The former has a fixed temperature and the latter has a range of temperatures that varies from one sightline to another. The models require a dust-gas temperature difference of 0$\\pm 2 $K and suggest that 40-50% of the Orion clouds are in the form of dust and gas with temperatures between 3 and 10$ $K. These results have a number implications that are discussed in detail in later papers. These include stronger dust-gas thermal coupling and higher Galactic-scale molecular gas temperatures than are usually accepted, an improved explanation for the N(H$_2$)/I(CO) conversion factor, and ruling out one dust grain alignment mechanism.

  3. Spectral Noise Correlations of an Ultrafast Frequency Comb

    E-Print Network [OSTI]

    Roman Schmeissner; Jonathan Roslund; Claude Fabre; Nicolas Treps

    2014-10-16T23:59:59.000Z

    Cavity-based noise detection schemes are combined with ultrafast pulse shaping as a means to diagnose the spectral correlations of both the amplitude and phase noise of an ultrafast frequency comb. The comb is divided into ten spectral regions, and the distribution of noise as well as the correlations between all pairs of spectral regions are measured against the quantum limit. These correlations are then represented in the form of classical noise matrices, which furnish a complete description of the underlying comb dynamics. Their eigendecomposition reveals a set of theoretically predicted, decoupled noise modes that govern the dynamics of the comb. Finally, the matrices contain the information necessary to deduce macroscopic noise properties of the comb.

  4. Ultrafast time-division demultiplexing of polarization-entangled photons

    E-Print Network [OSTI]

    John M. Donohue; Jonathan Lavoie; Kevin J. Resch

    2014-10-16T23:59:59.000Z

    Maximizing the information transmission rate through quantum channels is essential for practical implementation of quantum communication. Time-division multiplexing is an approach for which the ultimate rate requires the ability to manipulate and detect single photons on ultrafast timescales while preserving their quantum correlations. Here we demonstrate the demultiplexing of a train of pulsed single photons using time-to-frequency conversion while preserving their polarization entanglement with a partner photon. Our technique converts a pulse train with 2.69 ps spacing to a frequency comb with 307 GHz spacing which may be resolved using diffraction techniques. Our work enables ultrafast multiplexing of quantum information with commercially available single-photon detectors.

  5. Ultrafast dynamics of excitons in tetracene single crystals

    SciTech Connect (OSTI)

    Birech, Zephania; Schwoerer, Heinrich, E-mail: heso@sun.ac.za [Laser Research Institute, Stellenbosch University, Stellenbosch 7600 (South Africa)] [Laser Research Institute, Stellenbosch University, Stellenbosch 7600 (South Africa); Schwoerer, Markus [Department of Physics, University of Bayreuth, Bayreuth (Germany)] [Department of Physics, University of Bayreuth, Bayreuth (Germany); Schmeiler, Teresa; Pflaum, Jens [Experimental Physics VI, University of Würzburg and Bavarian Center for Applied Energy Research, Würzburg (Germany)] [Experimental Physics VI, University of Würzburg and Bavarian Center for Applied Energy Research, Würzburg (Germany)

    2014-03-21T23:59:59.000Z

    Ultrafast exciton dynamics in free standing 200 nm thin tetracene single crystals were studied at room temperature by femtosecond transient absorption spectroscopy in the visible spectral range. The complex spectrally overlapping transient absorption traces of single crystals were systematically deconvoluted. From this, the ultrafast dynamics of the ground, excited, and transition states were identified including singlet exciton fission into two triplet excitons. Fission is generated through both, direct fission of higher singlet states S{sub n} on a sub-picosecond timescale, and thermally activated fission of the singlet exciton S{sub 1} on a 40 ps timescale. The high energy Davydov component of the S{sub 1} exciton is proposed to undergo fission on a sub-picoseconds timescale. At high density of triplet excitons their mutual annihilation (triplet-triplet annihilation) occurs on a <10 ps timescale.

  6. Ultra-fast Laser Synthesis of Nanopore Arrays in Silicon for Bio-molecule Separation and Detection

    SciTech Connect (OSTI)

    Tringe, J W; Ileri, N; Letant, S E; Stroeve, P; Shirk, M; Zaidi, S; Balhorn, R L; Siders, C W

    2008-02-07T23:59:59.000Z

    We demonstrate that interference of ultra-fast pulses of laser light can create regular patterns in thin silicon membranes that are compatible with the formation of a uniform array of nanopores. The spacing and size of these pores can be tuned by changing the laser energy, wavelength and number of ultra-short pulses. Short pulses and wavelengths ({approx}550 nm and smaller) are needed to define controllable nanoscale features in silicon. Energy must be localized in time and space to produce the etching, ablation or amorphization effects over the {approx}100 nm length scales appropriate for definition of single pores. Although in this brief study pattern uniformity was limited by laser beam quality, a complementary demonstration reported here used continuous-wave interferometric laser exposure of photoresist to show the promise of the ultra-fast approach for producing uniform pore arrays. The diameters of these interferometrically-defined features are significantly more uniform than the diameters of pores in state-of-the-art polycarbonate track etch membranes widely used for molecular separations.

  7. Broadband laser cooling of trapped atoms with ultrafast pulses

    E-Print Network [OSTI]

    B. B. Blinov; R. N. Kohn Jr.; M. J. Madsen; P. Maunz; D. L. Moehring; C. Monroe

    2005-07-07T23:59:59.000Z

    We demonstrate broadband laser cooling of atomic ions in an rf trap using ultrafast pulses from a modelocked laser. The temperature of a single ion is measured by observing the size of a time-averaged image of the ion in the known harmonic trap potential. While the lowest observed temperature was only about 1 K, this method efficiently cools very hot atoms and can sufficiently localize trapped atoms to produce near diffraction-limited atomic images.

  8. ULTRACAM - an ultra-fast, triple-beam CCD camera

    E-Print Network [OSTI]

    Vik Dhillon; Tom Marsh; the ULTRACAM team

    2001-10-01T23:59:59.000Z

    ULTRACAM is an ultra-fast, triple-beam CCD camera which has been designed to study one of the few remaining unexplored regions of observational parameter space - high temporal resolution. The camera will see first light in Spring 2002, at a total cost of GBP 300 k, and will be used on 2-m, 4-m and 8-m class telescopes to study astrophysics on the fastest timescales.

  9. Ultrafast Time-Resolved Electron Diffraction with Megavolt Electron Beams

    SciTech Connect (OSTI)

    Hastings, J.B.; /SLAC; Rudakov, F.M.; /Brown U.; Dowell, D.H.; Schmerge, J.F.; /SLAC; Cardoza, J.D.; /Brown U.; Castro, J.M.; Gierman, S.M.; Loos, H.; /SLAC; Weber, P.M.; /Brown U.

    2006-10-24T23:59:59.000Z

    An rf photocathode electron gun is used as an electron source for ultrafast time-resolved pump-probe electron diffraction. We observed single-shot diffraction patterns from a 160 nm Al foil using the 5.4 MeV electron beam from the Gun Test Facility at the Stanford Linear Accelerator. Excellent agreement with simulations suggests that single-shot diffraction experiments with a time resolution approaching 100 fs are possible.

  10. Femtosecond-scale response of GaAs to ultrafast laser pulses Traian Dumitrica* and Roland E. Allen

    E-Print Network [OSTI]

    Allen, Roland E.

    Femtosecond-scale response of GaAs to ultrafast laser pulses Traian Dumitrica* and Roland E. Allen ordinary heating of the sample by phonon emission, there is convinc- ing evidence that ultrafast pulses of the initial stages of the interaction of a laser pulse with a semiconductor, which show that ultrafast disor

  11. 1966 JOURNAL OF LIGHTWAVE TECHNOLOGY, VOL. 15, NO. 10, OCTOBER 1997 Mode Conversion of Ultrafast Pulses by Grating

    E-Print Network [OSTI]

    Ziolkowski, Richard W.

    conversion of an ultrafast, ultrawide-bandwidth optical pulse propagating in a layered di- electric waveguide for an ultrafast six-cycle optical pulse over that achieved with standard uniform grating convertors. Index Terms--Dielectric waveguides, FDTD, mode conversion, mode extraction, numerical modeling, ultrafast optical pulses. I

  12. Ultrafast laser ablation ICP-MS: role of spot size, laser fluence, and repetition rate in signal intensity

    E-Print Network [OSTI]

    Harilal, S. S.

    Ultrafast laser ablation ICP-MS: role of spot size, laser fluence, and repetition rate in signal,a Richard E. Russob and Ahmed Hassaneina Ultrafast laser ablation inductively coupled plasma mass system. Though ultrafast laser ablation sample introduction provides better accuracy and precision

  13. Ultrafast charge localization in a stripe-phase nickelate

    SciTech Connect (OSTI)

    Coslovich, Giacomo; Huber, Bernhard; Lee, Wei-Sheng; Sasagawa, Takao; Hussain, Zahid; Bechtel, Hans A.; Martin, Michael C.; Shen, Zhi-Xun; W. Schoenlein, Robert; A. Kaindl, Robert

    2013-08-30T23:59:59.000Z

    Self-organized electronically-ordered phases are a recurring feature in correlated materials, resulting in e.g. fluctuating charge stripes whose role in high-Tc superconductivity is under debate. However, the relevant cause-effect relations between real-space charge correlations and low-energy excitations remain hidden in time-averaged studies. Here, we reveal ultrafast charge localization and lattice vibrational coupling as dynamical precursors of stripe formation in the model compound La1.75Sr0.25NiO4, using ultrafast and equilibrium mid-infrared spectroscopy. The opening of a pseudogap at a crossover temperature T* far above long-range stripe formation establishes the onset of electronic localization which is accompanied by an enhanced Fano asymmetry of Ni-O stretch vibrations. Ultrafast excitation triggers a sub-picosecond dynamics exposing the synchronous modulation of electron-phonon coupling and charge localization. These results illuminate the role of localization in forming the pseudogap in nickelates, opening a path to understanding this mysterious phase in a broad class of complex oxides.

  14. Physical properties and band structure of reactive molecular beam epitaxy grown oxygen engineered HfO{sub 2{+-}x}

    SciTech Connect (OSTI)

    Hildebrandt, Erwin; Kurian, Jose; Alff, Lambert [Institute of Materials Science, Technische Universitaet Darmstadt, 64287 Darmstadt (Germany)

    2012-12-01T23:59:59.000Z

    We have conducted a detailed thin film growth structure of oxygen engineered monoclinic HfO{sub 2{+-}x} grown by reactive molecular beam epitaxy. The oxidation conditions induce a switching between (111) and (002) texture of hafnium oxide. The band gap of oxygen deficient hafnia decreases with increasing amount of oxygen vacancies by more than 1 eV. For high oxygen vacancy concentrations, defect bands form inside the band gap that induce optical transitions and p-type conductivity. The resistivity changes by several orders of magnitude as a function of oxidation conditions. Oxygen vacancies do not give rise to ferromagnetic behavior.

  15. PHYSICAL REVIEW B 85, 205440 (2012) Inelastic neutron scattering investigations of the quantum molecular dynamics of a H2 molecule

    E-Print Network [OSTI]

    Turro, Nicholas J.

    2012-01-01T23:59:59.000Z

    PHYSICAL REVIEW B 85, 205440 (2012) Inelastic neutron scattering investigations of the quantum transfer arising from the neutron scattering event has also been investigated. The -dependence spectra investigations using infrared (IR),3,13­15 inelastic neutron scattering (INS),3,16,17 and nuclear magnetic

  16. PHYSICAL REVIEW B 86, 104114 (2012) Molecular dynamics of irradiation-induced defect production in GaN nanowires

    E-Print Network [OSTI]

    Nordlund, Kai

    2012-01-01T23:59:59.000Z

    in GaN nanowires Wei Ren,* Antti Kuronen, and Kai Nordlund Department of Physics, University of Helsinki the defect production of small-cross-section GaN nanowires by Ar ion irradiation. We performed 200 random production in the nanowires was increased by a factor of 2 compared to bulk GaN. A simple model to estimate

  17. Analytic model of electron pulse propagation in ultrafast electron diffraction experiments

    E-Print Network [OSTI]

    Sipe,J. E.

    Analytic model of electron pulse propagation in ultrafast electron diffraction experiments A. M pulses used in ultrafast electron diffraction experiments UED . We assume a Gaussian form to characterize the electron pulse, and derive a system of ordinary differential equations that are solved quickly and easily

  18. Adaptive all-order dispersion compensation of ultrafast laser pulses using dynamic spectral holography

    E-Print Network [OSTI]

    Nolte, David D.

    Adaptive all-order dispersion compensation of ultrafast laser pulses using dynamic spectral-1396 Received 14 July 1999; accepted for publication 24 September 1999 The time-varying dispersion of ultrafast laser pulses can be self-adaptively stabilized using real-time dynamic spectral holography

  19. Ultrafast Dynamics and Phase Changes in Solids Excited by Femtosecond Laser Pulses

    E-Print Network [OSTI]

    Mazur, Eric

    Ultrafast Dynamics and Phase Changes in Solids Excited by Femtosecond Laser Pulses A thesis pulse excites 1­20% of the valence electrons. We developed a broadband pump-probe technique to measure femtoseconds. The dielectric function provides more information than ever before on the ultrafast electronic

  20. Numerical simulations of self-focusing of ultrafast laser pulses Gadi Fibich*

    E-Print Network [OSTI]

    Wang, Xiao-Ping

    Numerical simulations of self-focusing of ultrafast laser pulses Gadi Fibich* School November 2002; published 7 May 2003 Simulation of nonlinear propagation of intense ultrafast laser pulses, space-time focusing, and self-steepening. Our simulations show that, after the asymmetric temporal pulse

  1. Ultrafast control of donor-bound electron spins with single detuned optical pulses

    E-Print Network [OSTI]

    Loss, Daniel

    LETTERS Ultrafast control of donor-bound electron spins with single detuned optical pulses KAI on microwave sources--can be attained with broadband optical pulses. One promising ultrafast technique uses single broadband pulses detuned from resonance in a three-level system4 . This technique is robust

  2. 644 OPTICS LETTERS / Vol. 29, No. 6 / March 15, 2004 General ultrafast pulse measurement using the

    E-Print Network [OSTI]

    644 OPTICS LETTERS / Vol. 29, No. 6 / March 15, 2004 General ultrafast pulse measurement using the cross-correlation single-shot sonogram technique Derryck T. Reid and Jesus Garduno-Mejia Ultrafast technique offers exact pulse measurement and real-time pulse monitoring via an intuitive time

  3. A pulsed electron gun for ultrafast electron diffraction at surfaces A. Janzen,a

    E-Print Network [OSTI]

    von der Linde, D.

    A pulsed electron gun for ultrafast electron diffraction at surfaces A. Janzen,a B. Krenzer, O The construction of a pulsed electron gun for ultrafast reflection high-energy electron diffraction experiments: a photocathode, consisting of a 10 nm thin Au film deposited onto a sapphire substrate. Electron pulses

  4. Laser pulse control of ultrafast heterogeneous electron transfer: A computational study

    E-Print Network [OSTI]

    Röder, Beate

    Laser pulse control of ultrafast heterogeneous electron transfer: A computational study Luxia Wang on ultrafast HET given in Refs. 14­16. In the following we will focus on the case where a tailored laser pulse, Germany Received 31 March 2004; accepted 30 July 2004 Laser pulse control of the photoinduced 90 fs charge

  5. RADIATION HEAT TRANSFER IN TISSUE WELDING AND SOLDERING WITH ULTRAFAST LASERS

    E-Print Network [OSTI]

    Guo, Zhixiong "James"

    RADIATION HEAT TRANSFER IN TISSUE WELDING AND SOLDERING WITH ULTRAFAST LASERS Kyunghan Kim to incorporate transient radiation heat transfer in tissue welding and soldering with use of ultrafast lasers are performed between laser welding and laser soldering. The use of solder is found to substantially enhance

  6. Ultrafast Third Harmonic Micro-spectroscopy Reveals a Two-Photon Resonance in Human Hemoglobin

    E-Print Network [OSTI]

    Kleinfeld, David

    Ultrafast Third Harmonic Micro-spectroscopy Reveals a Two-Photon Resonance in Human Hemoglobin G Golden, CO 80401 Abstract The recently developed technique of ultrafast third harmonic generation (THG states in physiological solutions of human hemoglobin. Keywords: Third Harmonic Generation, Micro

  7. Size-dependent ultrafast structural dynamics inside phospholipid vesicle bilayers measured with 2D IR

    E-Print Network [OSTI]

    Fayer, Michael D.

    Size-dependent ultrafast structural dynamics inside phospholipid vesicle bilayers measured with 2D 25, 2013) The ultrafast structural dynamics inside the bilayers of dilauroyl- phosphatidylcholine was used as a vibrational probe and provided information on spectral diffusion (structural dynam- ics

  8. Ultrafast dynamics of the laser-induced solid-to-liquid phase transition in aluminum

    E-Print Network [OSTI]

    Mazur, Eric

    Ultrafast dynamics of the laser-induced solid-to-liquid phase transition in aluminum A thesis dynamics of the laser-induced solid-to-liquid phase transition in aluminum Eric Mazur Maria Kandyla Abstract This dissertation reports the ultrafast dynamics of aluminum during the solid-to- liquid phase

  9. Physics high-ranking Journals (category 2) Advances in Physics

    E-Print Network [OSTI]

    Physics high-ranking Journals (category 2) Advances in Physics Annual Review of Astronomy and Astrophysics Annual Review of Nuclear and Particle Science Applied Physics Letters Astronomy & Astrophysics Astronomy and Astrophysics Review Astrophysical Journal European Physical Journal D. Atomic, Molecular

  10. INSTITUTE OF PHYSICS PUBLISHING JOURNAL OF PHYSICS B: ATOMIC, MOLECULAR AND OPTICAL PHYSICS J. Phys. B: At. Mol. Opt. Phys. 37 (2004) R57R88 PII: S0953-4075(04)63251-2

    E-Print Network [OSTI]

    Zajfman, Daniel

    of the high-energy storage rings used in high-energy particle physics, in particular LEAR [8], and use mainly, they are usually smaller and require neither high-energy (MeV) accelerators for injecting the beam, nor and nuclear physics, nonlinear dynamics, single component plasmas, mass spectrometry, biophysics, quantum

  11. CHEMICAL AND PHYSICAL CONDITIONS IN MOLECULAR CLOUD CORE DC 000.4-19.5 (SL42) IN CORONA AUSTRALIS

    SciTech Connect (OSTI)

    Hardegree-Ullman, E.; Whittet, D. C. B. [New York Center for Astrobiology and Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute, 110 Eighth Street, Troy, NY 12180 (United States)] [New York Center for Astrobiology and Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute, 110 Eighth Street, Troy, NY 12180 (United States); Harju, J. [Finnish Centre for Astronomy with ESO (FINCA), University of Turku, Vaeisaelaentie 20, FI-21500, Piikkioe (Finland)] [Finnish Centre for Astronomy with ESO (FINCA), University of Turku, Vaeisaelaentie 20, FI-21500, Piikkioe (Finland); Juvela, M.; Sipilae, O. [Department of Physics, P.O. Box 64, FI-00014, University of Helsinki (Finland)] [Department of Physics, P.O. Box 64, FI-00014, University of Helsinki (Finland); Hotzel, S., E-mail: hardee@rpi.edu [Observatory, FI-00014, University of Helsinki (Finland)

    2013-01-20T23:59:59.000Z

    Chemical reactions in starless molecular clouds are heavily dependent on interactions between gas phase material and solid phase dust and ices. We have observed the abundance and distribution of molecular gases in the cold, starless core DC 000.4-19.5 (SL42) in Corona Australis using data from the Swedish ESO Submillimeter Telescope. We present column density maps determined from measurements of C{sup 18}O (J = 2-1, 1-0) and N{sub 2}H{sup +} (J = 1-0) emission features. Herschel data of the same region allow a direct comparison to the dust component of the cloud core and provide evidence for gas phase depletion of CO at the highest extinctions. The dust color temperature in the core calculated from Herschel maps ranges from roughly 10.7 to 14.0 K. This range agrees with the previous determinations from Infrared Space Observatory and Planck observations. The column density profile of the core can be fitted with a Plummer-like density distribution approaching n(r) {approx} r {sup -2} at large distances. The core structure deviates clearly from a critical Bonnor-Ebert sphere. Instead, the core appears to be gravitationally bound and to lack thermal and turbulent support against the pressure of the surrounding low-density material: it may therefore be in the process of slow contraction. We test two chemical models and find that a steady-state depletion model agrees with the observed C{sup 18}O column density profile and the observed N(C{sup 18}O) versus A{sub V} relationship.

  12. Rise time measurement for ultrafast X-ray pulses

    DOE Patents [OSTI]

    Celliers, Peter M. (Berkeley, CA); Weber, Franz A. (Oakland, CA); Moon, Stephen J. (Tracy, CA)

    2005-04-05T23:59:59.000Z

    A pump-probe scheme measures the rise time of ultrafast x-ray pulses. Conventional high speed x-ray diagnostics (x-ray streak cameras, PIN diodes, diamond PCD devices) do not provide sufficient time resolution to resolve rise times of x-ray pulses on the order of 50 fs or less as they are being produced by modern fast x-ray sources. Here, we are describing a pump-probe technique that can be employed to measure events where detector resolution is insufficient to resolve the event. The scheme utilizes a diamond plate as an x-ray transducer and a p-polarized probe beam.

  13. Photoionisation loading of large Sr+ ion clouds with ultrafast pulses

    E-Print Network [OSTI]

    Sébastien Removille; Romain Dubessy; Quentin Glorieux; Samuel Guibal; Thomas Coudreau; Luca Guidoni; Jean-Pierre Likforman

    2008-12-05T23:59:59.000Z

    This paper reports on photoionisation loading based on ultrafast pulses of singly-ionised strontium ions in a linear Paul trap. We take advantage of an autoionising resonance of Sr neutral atoms to form Sr+ by two-photon absorption of femtosecond pulses at a wavelength of 431nm. We compare this technique to electron-bombardment ionisation and observe several advantages of photoionisation. It actually allows the loading of a pure Sr+ ion cloud in a low radio-frequency voltage amplitude regime. In these conditions up to 4x10^4 laser-cooled Sr+ ions were trapped.

  14. Ultrafast laser control of backward superfluorescence towards standoff sensing

    SciTech Connect (OSTI)

    Ariunbold, Gombojav O. [Texas A and M University, College Station, Texas 77843 (United States); National University of Mongolia, Ulaanbaatar 210646 (Mongolia); Baylor University, Waco, Texas 76798 (United States); Sautenkov, Vladimir A. [Texas A and M University, College Station, Texas 77843 (United States); Joint Institute for High Temperatures, Russian Academy of Sciences, Moscow 125412 (Russian Federation); P. N. Lebedev Physical Institute, Russian Academy of Sciences, Moscow 119991 (Russian Federation); Rostovtsev, Yuri V. [University of North Texas, Denton, Texas 76203 (United States); Scully, Marlan O. [Texas A and M University, College Station, Texas 77843 (United States); Baylor University, Waco, Texas 76798 (United States); Princeton University, Princeton, New Jersey 08544 (United States)

    2014-01-13T23:59:59.000Z

    We study infrared backward cooperative emission in a rubidium vapor induced by ultrafast two-photon optical excitations. The laser coherent control of the backward emission is demonstrated by using a pair of 100 fs pulses with a variable time delay. The temporal variation (quantum beat) of the backward beam intensity due to interference of atomic transitions in the rubidium atomic level system 5S-5P-5D is produced and controlled. Based on the obtained experimental results, we discuss possible applications of the developed approach for creation of an effective “guide star” in the sodium atomic layer in the upper atmosphere (mesosphere)

  15. Rise Time Measurement for Ultrafast X-Ray Pulses

    DOE Patents [OSTI]

    Celliers, Peter M.; Weber, Franz A.; Moon, Stephen J.

    2005-04-05T23:59:59.000Z

    A pump-probe scheme measures the rise time of ultrafast x-ray pulses. Conventional high speed x-ray diagnostics (x-ray streak cameras, PIN diodes, diamond PCD devices) do not provide sufficient time resolution to resolve rise times of x-ray pulses on the order of 50 fs or less as they are being produced by modern fast x-ray sources. Here, we are describing a pump-probe technique that can be employed to measure events where detector resolution is insufficient to resolve the event. The scheme utilizes a diamond plate as an x-ray transducer and a p-polarized probe beam.

  16. Optical Damage Threshold of Silicon for Ultrafast Infrared Pulses

    SciTech Connect (OSTI)

    Cowan, Benjamin M.; /Tech-X, Boulder /SLAC

    2007-11-28T23:59:59.000Z

    We present measurements of the optical damage threshold of crystalline silicon in air for ultrafast pulses in the near infrared. The wavelengths tested span a range from the telecommunications band at 1550 nm, extending to 2260 nm. We discuss the motivation for the measurements and give theoretical context. We then describe the experimental setup, diagnostics, and procedure. The results show a breakdown threshold of 0.2J/cm{sup 2} at 1550 nm and 1.06 ps FWHM pulse duration, and a weak dependence on wavelength.

  17. Ultrafast Core-Hole Induced Dynamics in Water

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What'sis Taking Over OurThe Iron Spin TransitionProgram |Frank CasellaEnergyUltracold Atoms: HowUltrafast

  18. Ultrafast Core-Hole Induced Dynamics in Water

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What'sis Taking Over OurThe Iron Spin TransitionProgram |Frank CasellaEnergyUltracold Atoms:Ultrafast

  19. Ultrafast Core-Hole Induced Dynamics in Water

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of ScienceandMesa del SolStrengthening aTurbulence may bedieselsummerFact SheetsUltrafast Core-Hole

  20. Ultrafast Core-Hole Induced Dynamics in Water

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of ScienceandMesa del SolStrengthening aTurbulence may bedieselsummerFact SheetsUltrafast

  1. Double Wall Carbon Nanotubes for Wide-Band, Ultrafast Pulse Generation

    E-Print Network [OSTI]

    Hasan, Tawfique; Sun, Zhipei; Tan, PingHeng; Popa, Daniel; Flahaut, Emmanuel; Kelleher, Edmund J. R.; Bonaccorso, Francesco; Wang, Fengqiu; Jiang, Zhe; Torrisi, Felice; Privitera, Giulia; Nicolosi, Valeria; Ferrari, Andrea C.

    2014-04-15T23:59:59.000Z

    Accepted Manuscript: ACS Nano, 2014, 8 (5), pp 4836–4847DOI: 10.1021/nn500767b 1 Double Wall Carbon Nanotubes for Wide-Band, Ultrafast Pulse Generation Tawfique Hasan1,*, Zhipei Sun2, PingHeng Tan3, Daniel Popa1, Emmanuel Flahaut4,5, Edmund J. R... , Polymer Composites, Saturable Absorber, Ultrafast Laser. Accepted Manuscript: ACS Nano, 2014, 8 (5), pp 4836–4847DOI: 10.1021/nn500767b 2 ABSTRACT: We demonstrate wideband ultrafast optical pulse generation at 1, 1.5 and 2?m using a single polymer...

  2. Development of ZnO:Ga as an Ultrafast Scintillator

    SciTech Connect (OSTI)

    Bourret-Courchesne, E.D.; Derenzo, S.E.; Weber, M.J.

    2008-12-10T23:59:59.000Z

    We report on several methods for synthesizing the ultra-fast scintillator ZnO(Ga), and measurements of the resulting products. This material has characteristics that make it an excellent alpha detector for tagging the time and direction of individual neutrons produced by t-d and d-d neutron generators (associated particle imaging). The intensity and decay time are strongly dependent on the method used for dopant incorporation. We compare samples made by diffusion of Ga metal to samples made by solid state reaction between ZnO and Ga2O3 followed by reduction in hydrogen. The latter is much more successful and has a pure, strong near-band-edge fluorescence and an ultra-fast decay time of the x-ray-excited luminescence. The luminescence increases dramatically as the temperature is reduced to 10K. We also present results of an alternate low-temperature synthesis that produces luminescent particles with a more uniform size distribution. We examine possible mechanisms for the bright near-band-edge scintillation and favor the explanation that it is due to the recombination of Ga3+ donor electrons with ionization holes trapped on H+ ion acceptors.

  3. Two-Color Ultrafast Photoexcited Scanning Tunneling Microscopy

    SciTech Connect (OSTI)

    Camillone, N.; Dolocan, A.; Acharya, D.P.; Zahl, P.; Sutter, P.

    2011-05-26T23:59:59.000Z

    We report on two-color two-photon photoexcitation of a metal surface driven by ultrafast laser pulses and detected with a scanning tunneling microscope (STM) tip as a proximate anode. Results are presented for two cases: (i) where the tip is retracted from the surface far enough to prohibit tunneling, and (ii) where the tip is within tunneling range of the surface. A delay-modulation technique is implemented to isolate the two-color photoemission from concurrent one-color two-photon photoemission and provide subpicosecond time-resolved detection. When applied with the tip in tunneling range, this approach effectively isolates the two-photon photoexcited current signal from the conventional tunneling current and enables subpicosecond time-resolved detection of the photoexcited surface electrons. The advantage of the two-color approach is highlighted by comparison with the one-color case where optical interference causes thermal modulation of the STM tip length, resulting in tunneling current modulations that are orders of magnitude larger than the current due to photoexcitation of surface electrons. By completely eliminating this interference, and thereby avoiding thermal modulation of the STM tip length, the two-color approach represents an important step toward the ultimate goal of simultaneous subnanometer and subpicosecond measurements of surface electron dynamics by ultrafast-laser-excited STM.

  4. Atomic Resolution Coherent Diffractive Imaging and Ultrafast Science

    SciTech Connect (OSTI)

    Zuo, Jian-min (University of Illinois) [University of Illinois

    2011-01-12T23:59:59.000Z

    A major scientific challenge is determining the 3-D atomic structure of small nanostructures, including single molecules. Coherent diffractive imaging (CDI) is a promising approach. Recent progress has demonstrated coherent diffraction patterns can be recorded from individual nanostructures and phased to reconstruct their structure. However, overcoming the dose limit imposed by radiation damage is a major obstacle toward the full potential of CDI. One approach is to use ultrafast x-ray or electron pulses. In electron diffraction, amplitudes recorded in a diffraction pattern are unperturbed by lens aberrations, defocus, and other microscope resolution-limiting factors. Sub-A signals are available beyond the information limit of direct imaging. Significant contrast improvement is obtained compared to high-resolution electron micrographs. progress has also been made in developing time-resolved electron diffraction and imaging for the study of ultrafast dynamic processes in materials. This talk will cover these crosscutting issues and the convergence of electron and x-ray diffraction techniques toward structure determination of single molecules.

  5. Optical Nonlinearities and Ultrafast Carrier Dynamics in Semiconductor Quantum Dots

    SciTech Connect (OSTI)

    Klimov, V.; McBranch, D.; Schwarz, C.

    1998-08-10T23:59:59.000Z

    Low-dimensional semiconductors have attracted great interest due to the potential for tailoring their linear and nonlinear optical properties over a wide-range. Semiconductor nanocrystals (NC's) represent a class of quasi-zero-dimensional objects or quantum dots. Due to quantum cordhement and a large surface-to-volume ratio, the linear and nonlinear optical properties, and the carrier dynamics in NC's are significantly different horn those in bulk materials. napping at surface states can lead to a fast depopulation of quantized states, accompanied by charge separation and generation of local fields which significantly modifies the nonlinear optical response in NC's. 3D carrier confinement also has a drastic effect on the energy relaxation dynamics. In strongly confined NC's, the energy-level spacing can greatly exceed typical phonon energies. This has been expected to significantly inhibit phonon-related mechanisms for energy losses, an effect referred to as a phonon bottleneck. It has been suggested recently that the phonon bottleneck in 3D-confined systems can be removed due to enhanced role of Auger-type interactions. In this paper we report femtosecond (fs) studies of ultrafast optical nonlinearities, and energy relaxation and trap ping dynamics in three types of quantum-dot systems: semiconductor NC/glass composites made by high temperature precipitation, ion-implanted NC's, and colloidal NC'S. Comparison of ultrafast data for different samples allows us to separate effects being intrinsic to quantum dots from those related to lattice imperfections and interface properties.

  6. INSTITUTE OF PHYSICS PUBLISHING JOURNAL OF PHYSICS B: ATOMIC, MOLECULAR AND OPTICAL PHYSICS J. Phys. B: At. Mol. Opt. Phys. 37 (2004) 35513562 PII: S0953-4075(04)81883-2

    E-Print Network [OSTI]

    Roach, Timothy

    in an accelerating potential Timothy M Roach Physics Department, The College of the Holy Cross, Worcester, MA 01610 #12;3552 T M Roach y gUBU U atoms grating(a) (b) y Figure 1. (a) Cloud of atoms accelerated towards

  7. Dynamic Processes in Biology, Chemistry, and Materials Science: Opportunities for UltraFast Transmission Electron Microscopy - Workshop Summary Report

    SciTech Connect (OSTI)

    Kabius, Bernd C.; Browning, Nigel D.; Thevuthasan, Suntharampillai; Diehl, Barbara L.; Stach, Eric A.

    2012-07-25T23:59:59.000Z

    This report summarizes a 2011 workshop that addressed the potential role of rapid, time-resolved electron microscopy measurements in accelerating the solution of important scientific and technical problems. A series of U.S. Department of Energy (DOE) and National Academy of Science workshops have highlighted the critical role advanced research tools play in addressing scientific challenges relevant to biology, sustainable energy, and technologies that will fuel economic development without degrading our environment. Among the specific capability needs for advancing science and technology are tools that extract more detailed information in realistic environments (in situ or operando) at extreme conditions (pressure and temperature) and as a function of time (dynamic and time-dependent). One of the DOE workshops, Future Science Needs and Opportunities for Electron Scattering: Next Generation Instrumentation and Beyond, specifically addressed the importance of electron-based characterization methods for a wide range of energy-relevant Grand Scientific Challenges. Boosted by the electron optical advancement in the last decade, a diversity of in situ capabilities already is available in many laboratories. The obvious remaining major capability gap in electron microscopy is in the ability to make these direct in situ observations over a broad spectrum of fast (µs) to ultrafast (picosecond [ps] and faster) temporal regimes. In an effort to address current capability gaps, EMSL, the Environmental Molecular Sciences Laboratory, organized an Ultrafast Electron Microscopy Workshop, held June 14-15, 2011, with the primary goal to identify the scientific needs that could be met by creating a facility capable of a strongly improved time resolution with integrated in situ capabilities. The workshop brought together more than 40 leading scientists involved in applying and/or advancing electron microscopy to address important scientific problems of relevance to DOE’s research mission. This workshop built on previous workshops and included three breakout sessions identifying scientific challenges in biology, biogeochemistry, catalysis, and materials science frontier areas of fundamental science that underpin energy and environmental science that would significantly benefit from ultrafast transmission electron microscopy (UTEM). In addition, the current status of time-resolved electron microscopy was examined, and the technologies that will enable future advances in spatio-temporal resolution were identified in a fourth breakout session.

  8. Release mechanism of octadecyl rhodamine B chloride from Au nanorods by ultrafast laser pulses

    E-Print Network [OSTI]

    Alper, Joshua Daniel

    We investigated the release of octadecyl rhodamine B chloride (R[subscript 18]) loaded onto cetyltrimethylammonium bromide (CTAB) coated gold nanorods (NR) by pulsed ultrafast laser excitation. R[subscript 18] intercalates ...

  9. Two photon luminescence from quantum dots using broad and narrowband ultrafast laser pulses

    E-Print Network [OSTI]

    Balasubramanian, Haribhaskar

    2009-05-15T23:59:59.000Z

    Nonlinear optical microscopy (NLOM) offers many advantages when imaging intact biological samples. By using ultrafast lasers in the near infrared and two photon excitation (TPE), signal production is limited to the focal volume and provides...

  10. Electron Pulse Compression with a Practical Reflectron Design for Ultrafast Electron Diffraction

    E-Print Network [OSTI]

    Wang, Yihua

    Ultrafast electron diffraction (UED) is a powerful method for studying time-resolved structural changes. Currently, space-charge-induced temporal broadening prevents obtaining high-brightness electron pulses with sub-100 ...

  11. Ultrafast Cooperative Phenomena in Coherently Prepared Media: From Superfluorescence to Coherent Raman Scattering and Applications 

    E-Print Network [OSTI]

    Gombojav, Ariunbold

    2012-07-16T23:59:59.000Z

    Technological progress in commercializing ultrafast lasers and detectors has allowed realization of cooperative processes on an ultrashort time scale, which demand a re-evaluation of the conventional cooperative phenomena with a new insight...

  12. Two photon luminescence from quantum dots using broad and narrowband ultrafast laser pulses 

    E-Print Network [OSTI]

    Balasubramanian, Haribhaskar

    2009-05-15T23:59:59.000Z

    Nonlinear optical microscopy (NLOM) offers many advantages when imaging intact biological samples. By using ultrafast lasers in the near infrared and two photon excitation (TPE), signal production is limited to the focal volume and provides...

  13. Two photon luminescence from quantum dots using broad and narrowband ultrafast laser pulses 

    E-Print Network [OSTI]

    Balasubramanian, Haribhaskar

    2008-10-10T23:59:59.000Z

    Nonlinear optical microscopy (NLOM) offers many advantages when imaging intact biological samples. By using ultrafast lasers in the near infrared and two photon excitation (TPE), signal production is limited to the focal volume and provides...

  14. Hydrogen Bond Dynamics Probed with Ultrafast Infrared Heterodyne-Detected Multidimensional Vibrational Stimulated Echoes

    E-Print Network [OSTI]

    Fayer, Michael D.

    Hydrogen Bond Dynamics Probed with Ultrafast Infrared Heterodyne-Detected Multidimensional, USA (Received 24 February 2003; published 3 December 2003) Hydrogen bond dynamics are explicated hydrogen bonded network are measured with ultrashort (

  15. Synthesis, Characterization, and Ultrafast Dynamics of Metal, Metal Oxide, and Semiconductor Nanomaterials

    E-Print Network [OSTI]

    Wheeler, Damon Andreas

    2013-01-01T23:59:59.000Z

    and Photoelectrochemical Properties of Hydrogen-treated TiO2Photoelectrochemical Properties of Hydrogen-Treated TiO 2and ultrafast properties of hydrogen-treated TiO 2 ( H:TiO

  16. Sub-femtosecond precision timing distribution, synchronization and coherent synthesis of ultrafast lasers

    E-Print Network [OSTI]

    Cox, Jonathan A

    2012-01-01T23:59:59.000Z

    In this thesis, we present a complete set of techniques for sub-femtosecond measurement, control and distribution of ultrafast optical pulse trains, with respect to pulse timing and phase. First, analytical analysis of the ...

  17. Electromagnetically-driven ultra-fast tool servos for diamond turning

    E-Print Network [OSTI]

    Lu, Xiaodong, Ph. D. Massachusetts Institute of Technology

    2005-01-01T23:59:59.000Z

    This thesis presents the design, implementation, and control of a new class of fast tool servos (FTS). The primary thesis contributions include the design and experimental demonstration of: novel ultra-fast electromagnetic ...

  18. Direct Observation of Optically Induced Transient Structures in Graphite Using Ultrafast Electron Crystallography

    E-Print Network [OSTI]

    initio density functional calculations, we trace the governing mechanism back to electronic structure changes in the electronic properties, direct de- termination of lattice structural dynamics from opticalDirect Observation of Optically Induced Transient Structures in Graphite Using Ultrafast Electron

  19. Localized Excited Charge Carriers Generate Ultrafast Inhomogeneous Strain in the Multiferroic BiFeO3

    E-Print Network [OSTI]

    Evans, Paul G.

    Materialien und Energie GmbH, Wilhelm-Conrad-Röntgen Campus, BESSY II, Albert-Einstein-Straße 15, 12489 Berlin in a recent synchrotron-based ultrafast x-ray diffraction (UXRD) study with a temporal resolution of 100 ps

  20. Ultrafast Dynamics of 1,3-Cyclohexadiene in Highly Excited States

    E-Print Network [OSTI]

    Minitti, Michael P.

    2011-01-01T23:59:59.000Z

    The ultrafast dynamics of 1,3-cyclohexadiene has been investigated via structurally sensitive Rydberg electron binding energies and shown to differ upon excitation to the 1B state and the 3p Rydberg state. Excitation of ...

  1. Ultrafast Laser Induced Thermo-Elasto-Visco-Plastodynamics in Single Crystalline Silicon 

    E-Print Network [OSTI]

    Qi, Xuele

    2011-02-22T23:59:59.000Z

    A comprehensive model for describing the fundamental mechanism dictating the interaction of ultrafast laser pulse with single crystalline silicon wafer is formulated. The need for establishing the feasibility of employing lasers of subpicosecond...

  2. Collective Hydrogen Bond Reorganization in Water Studied with Temperature-Dependent Ultrafast Infrared Spectroscopy

    E-Print Network [OSTI]

    Nicodemus, Rebecca A.

    We use temperature-dependent ultrafast infrared spectroscopy of dilute HOD in H2O to study the picosecond reorganization of the hydrogen bond network of liquid water. Temperature-dependent two-dimensional infrared (2D IR), ...

  3. Ultrafast K{alpha} x-ray Thomson scattering from shock compressed lithium hydride

    SciTech Connect (OSTI)

    Kritcher, A. L. [L-399, Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551 (United States); Nuclear Engineering Department, University of California Berkeley, Berkeley, California 94709 (United States); Neumayer, P.; Castor, J.; Doeppner, T.; Landen, O. L.; Ng, A.; Pollaine, S.; Price, D.; Glenzer, S. H. [L-399, Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551 (United States); Falcone, R. W.; Lee, H. J. [Physics Department, University of California Berkeley, Berkeley, California 94709 (United States); Lee, R. W. [L-399, Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551 (United States); Physics Department, University of California Berkeley, Berkeley, California 94709 (United States); Holst, B.; Redmer, R. [Institut fuer Physik, Universitaet Rostock, D-18051 Rostock (Germany); Morse, E. C. [Nuclear Engineering Department, University of California Berkeley, Berkeley, California 94709 (United States)

    2009-05-15T23:59:59.000Z

    Spectrally and temporally resolved x-ray Thomson scattering using ultrafast Ti K{alpha} x rays has provided experimental validation for modeling of the compression and heating of shocked matter. The coalescence of two shocks launched into a solid density LiH target by a shaped 6 ns heater beam was observed from rapid heating to temperatures of 2.2 eV, enabling tests of shock timing models. Here, the temperature evolution of the target at various times during shock progression was characterized from the intensity of the elastic scattering component. The observation of scattering from plasmons, electron plasma oscillations, at shock coalescence indicates a transition to a dense metallic plasma state in LiH. From the frequency shift of the measured plasmon feature the electron density was directly determined with high accuracy, providing a material compression of a factor of 3 times solid density. The quality of data achieved in these experiments demonstrates the capability for single shot dynamic characterization of dense shock compressed matter. The conditions probed in this experiment are relevant for the study of the physics of planetary formation and to characterize inertial confinement fusion targets for experiments such as on the National Ignition Facility, Lawrence Livermore National Laboratory.

  4. Ultrafast K-(alpha) X-ray Thomson Scattering from Shock Compressed Lithium Hydride

    SciTech Connect (OSTI)

    Kritcher, A L; Neumayer, P; Castor, J; Doeppner, T; Falcone, R W; Landen, O L; Lee, H J; Lee, R W; Holst, B; Redmer, R; Morse, E C; Ng, A; Pollaine, S; Price, D; Glenzer, S H

    2008-12-10T23:59:59.000Z

    Spectrally and temporally resolved x ray Thomson scattering using ultrafast Ti K-{alpha} x-rays has provided experimental validation for modeling of the compression and heating of shocked matter. The coalescence of two shocks launched into a solid density LiH target by a shaped 6 nanosecond heater beam was observed from rapid heating to temperatures of 2.2 eV, enabling tests of shock timing models. Here, the temperature evolution of the target at various times during shock progression was characterized from the intensity of the elastic scattering component. The observation of scattering from plasmons, electron plasma oscillations, at shock coalescence indicates a transition to a dense metallic plasma state in LiH. From the frequency shift of the measured plasmon feature the electron density was directly determined with high accuracy, providing a material compression of a factor of three times solid density. The quality of data achieved in these experiments demonstrates the capability for single-shot dynamic characterization of dense shock compressed matter. The conditions probed in this experiment are relevant for the study of the physics of planetary formation and to characterize inertial confinement fusion targets for experiments such as on the National Ignition Facility (NIF), LLNL.

  5. Two photon luminescence from quantum dots using broad and narrowband ultrafast laser pulses

    E-Print Network [OSTI]

    Balasubramanian, Haribhaskar

    2008-10-10T23:59:59.000Z

    TWO PHOTON LUMINESCENCE FROM QUANTUM DOTS USING BROAD AND NARROWBAND ULTRAFAST LASER PULSES A Thesis by HARIBHASKAR BALASUBRAMANIAN Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment... of the requirements for the degree of MASTER OF SCIENCE December 2007 Major Subject: Biomedical Engineering TWO PHOTON LUMINESCENCE FROM QUANTUM DOTS USING BROAD AND NARROWBAND ULTRAFAST LASER PULSES A Thesis by HARIBHASKAR...

  6. IOP PUBLISHING JOURNAL OF PHYSICS B: ATOMIC, MOLECULAR AND OPTICAL PHYSICS J. Phys. B: At. Mol. Opt. Phys. 42 (2009) 105201 (5pp) doi:10.1088/0953-4075/42/10/105201

    E-Print Network [OSTI]

    Bapat, Bhas

    of core and valence electron excitation in molecules and the dissociation dynamics under such excitations- coincidence technique may permit reconstruction of the geometry of the excited molecular ion. As an example in excitation into a discrete molecular orbital as a function of the molecular alignment has been studied

  7. Study of the subpicosecond rotational molecular dynamics in liquids

    SciTech Connect (OSTI)

    Nikiforov, V G; Lobkov, Vladimir S [E.K.Zavoisky Physical-Technical Institute, Kazan Scientific Center, Russian Academy of Sciences, Kazan (Russian Federation)

    2006-10-31T23:59:59.000Z

    The parameters of the femtosecond vibration-rotation molecular dynamics of liquid acetonitrile CH{sub 3}CN, trimethylacetonitrile (CH{sub 3}){sub 3}CCN, propionitrile CH{sub 3}CH{sub 2}CN, fluoroform CHF{sub 3}, and chloroform CHCl{sub 3} are found by analysing the ultrafast optical Kerr effect. The influence of the molecular structure on the features of rotational (diffusion and libration) motions is studied. It is shown that the distribution of libration frequencies is described by the Maxwell distribution. (laser applications and other topics in quantum electronics)

  8. Ultrafast Extreme Ultraviolet Induced Isomerization of Acetylene Cations

    E-Print Network [OSTI]

    Jiang, Y.

    2012-01-01T23:59:59.000Z

    PHYSICAL REVIEW LETTERS PRL 105, 263002 (2010) week endingAmerican Physical Society PRL 105, 263002 (2010) PHYSICALcould not be distinguished. PRL 105, 263002 (2010) PHYSICAL

  9. Performance of volume phase gratings manufactured using ultrafast laser inscription

    E-Print Network [OSTI]

    Lee, David; Cunningham, Colin R

    2012-01-01T23:59:59.000Z

    Ultrafast laser inscription (ULI) is a rapidly maturing technique which uses focused ultrashort laser pulses to locally modify the refractive index of dielectric materials in three-dimensions (3D). Recently, ULI has been applied to the fabrication of astrophotonic devices such as integrated beam combiners, 3D integrated waveguide fan-outs and multimode-to-single mode convertors (photonic lanterns). Here, we outline our work on applying ULI to the fabrication of volume phase gratings (VPGs) in fused silica and gallium lanthanum sulphide (GLS) glasses. The VPGs we fabricated had a spatial frequency of 333 lines/mm. The optimum fused silica grating was found to exhibit a first order diffraction efficiency of 40 % at 633 nm, but exhibited approximately 40 % integrated scattered light. The optimum GLS grating was found to exhibit a first order diffraction efficiency of 71 % at 633 nm and less than 5 % integrated scattered light. Importantly for future astronomy applications, both gratings survived cooling to 20 K....

  10. Ultrafast stimulated Raman parallel adiabatic passage by shaped pulses

    E-Print Network [OSTI]

    G. Dridi; S. Guerin; V. Hakobyan; H. R. Jauslin; H. Eleuch

    2009-10-06T23:59:59.000Z

    We present a general and versatile technique of population transfer based on {\\it parallel adiabatic passage} by femtosecond shaped pulses. Their amplitude and phase are specifically designed to optimize the adiabatic passage corresponding to parallel eigenvalues at all times. We show that this technique allows the robust adiabatic population transfer in a Raman system with the total pulse area as low as 3 $\\pi$, corresponding to a fluence of one order of magnitude below the conventional stimulated Raman adiabatic passage process. This process of short duration, typically pico- and subpicosecond, is easily implementable with the modern pulse shaper technology and opens the possibility of ultrafast robust population transfer with interesting applications in quantum information processing.

  11. Ultrafast electron diffraction with radio-frequency compressed electron pulses

    SciTech Connect (OSTI)

    Chatelain, Robert P.; Morrison, Vance R.; Godbout, Chris; Siwick, Bradley J. [Departments of Physics and Chemistry, Center for the Physics of Materials, McGill University, Montreal (Canada)

    2012-08-20T23:59:59.000Z

    We report on the complete characterization of time resolution in an ultrafast electron diffraction (UED) instrument based on radio-frequency electron pulse compression. The temporal impulse response function of the instrument was determined directly in pump-probe geometry by performing electron-laser pulse cross-correlation measurements using the ponderomotive interaction. With optimal settings, a stable impulse response of 334{+-}10 fs was measured at a bunch charge of 0.1 pC (6.24 Multiplication-Sign 10{sup 5} electrons/pulse); a dramatic improvement compared to performance without pulse compression. Phase stability currently limits the impulse response of the UED diffractometer to the range of 334-500 fs, for bunch charges ranging between 0.1 and 0.6 pC.

  12. Ultrafast laser diagnostics to investigate initiation fundamentals in energetic materials.

    SciTech Connect (OSTI)

    Farrow, Darcie; Jilek, Brook Anton; Kohl, Ian Thomas; Kearney, Sean Patrick

    2013-08-01T23:59:59.000Z

    We present the results of a two year early career LDRD project, which has focused on the development of ultrafast diagnostics to measure temperature, pressure and chemical change during the shock initiation of energetic materials. We compare two single-shot versions of femtosecond rotational CARS to measure nitrogen temperature: chirped-probe-pulse and ps/fs hybrid CARS thermometry. The applicability of measurements to the combustion of energetic materials will be discussed. We have also demonstrated laser shock and particle velocity measurements in thin film explosives using stretched femtosecond laser pulses. We will discuss preliminary results from Al and PETN thin films. Agreement between our results and previous work will be discussed.

  13. Ultrafast Extreme Ultraviolet Induced Isomerization of Acetylene Cations

    SciTech Connect (OSTI)

    Jiang, Y. H.; Kurka, M.; Kuehnel, K. U.; Schroeter, C. D.; Moshammer, R. [Max-Planck-Institut fuer Kernphysik, 69117 Heidelberg (Germany); Rudenko, A.; Foucar, L. [Max-Planck Advanced Study Group at CFEL, 22607 Hamburg (Germany); Herrwerth, O.; Lezius, M.; Kling, M. F. [Max-Planck-Institut fuer Quantenoptik, 85748 Garching (Germany); Tilborg, J. van; Belkacem, A. [Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Ueda, K. [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 980-8577 Sendai (Japan); Duesterer, S.; Treusch, R. [DESY, 22607 Hamburg (Germany); Ullrich, J. [Max-Planck-Institut fuer Kernphysik, 69117 Heidelberg (Germany); Max-Planck Advanced Study Group at CFEL, 22607 Hamburg (Germany)

    2010-12-31T23:59:59.000Z

    Ultrafast isomerization of acetylene cations ([HC=CH]{sup +}) in the low-lying excited A{sup 2}{Sigma}{sub g}{sup +} state, populated by the absorption of extreme ultraviolet (XUV) photons (38 eV), has been observed at the Free Electron Laser in Hamburg, (FLASH). Recording coincident fragments C{sup +}+CH{sub 2}{sup +} as a function of time between XUV-pump and -probe pulses, generated by a split-mirror device, we find an isomerization time of 52{+-}15 fs in a kinetic energy release (KER) window of 5.8

  14. Ultrafast Extreme Ultraviolet Induced Isomerization of Acetylene Cations

    SciTech Connect (OSTI)

    Jiang, Y.; Rudenko, Artem; Herrwerth, O.; Foucar, L.; Kurka, M.; Kuhnel, K.; Lezius, M.; Kling, Matthias; van Tilborg, Jeroen; Belkacem, Ali; Ueda, K.; Dusterer, S.; Treusch, R.; Schroter, Claus-Dieter; Moshammer, Robbert; Ullrich, Joachim

    2011-06-17T23:59:59.000Z

    Ultrafast isomerization of acetylene cations ([HC = CH]{sup +}) in the low-lying excited A{sup 2}{Sigma}{sub g}{sup +} state, populated by the absorption of extreme ultraviolet (XUV) photons (38 eV), has been observed at the Free Electron Laser in Hamburg, (FLASH). Recording coincident fragments C{sup +} + CH{sub 2}{sup +} as a function of time between XUV-pump and -probe pulses, generated by a split-mirror device, we find an isomerization time of 52 {+-} 15 fs in a kinetic energy release (KER) window of 5.8 < KER < 8 eV, providing clear evidence for the existence of a fast, nonradiative decay channel.

  15. A pulsed electron gun for ultrafast electron diffraction at surfaces

    SciTech Connect (OSTI)

    Janzen, A.; Krenzer, B.; Heinz, O.; Zhou, P.; Thien, D.; Hanisch, A.; Meyer zu Heringdorf, F.-J.; Linde, D. von der; Horn von Hoegen, M. [Department of Physics and Centre for Nanointegration (CeNIDE), University of Duisburg-Essen, 47048 Duisburg (Germany)

    2007-01-15T23:59:59.000Z

    The construction of a pulsed electron gun for ultrafast reflection high-energy electron diffraction experiments at surfaces is reported. Special emphasis is placed on the characterization of the electron source: a photocathode, consisting of a 10 nm thin Au film deposited onto a sapphire substrate. Electron pulses are generated by the illumination of the film with ultraviolet laser pulses of femtosecond duration. The photoelectrons are emitted homogeneously across the photocathode with an energy distribution of 0.1 eV width. After leaving the Au film, the electrons are accelerated to kinetic energies of up to 15 keV. Focusing is accomplished by an electrostatic lens. The temporal resolution of the experiment is determined by the probing time of the electrons traveling across the surface which is about 30 ps. However, the duration of the electron pulses can be reduced to less than 6 ps.

  16. Atomic and molecular supernovae

    SciTech Connect (OSTI)

    Liu, W.

    1997-12-01T23:59:59.000Z

    Atomic and molecular physics of supernovae is discussed with an emphasis on the importance of detailed treatments of the critical atomic and molecular processes with the best available atomic and molecular data. The observations of molecules in SN 1987A are interpreted through a combination of spectral and chemical modelings, leading to strong constraints on the mixing and nucleosynthesis of the supernova. The non-equilibrium chemistry is used to argue that carbon dust can form in the oxygen-rich clumps where the efficient molecular cooling makes the nucleation of dust grains possible. For Type Ia supernovae, the analyses of their nebular spectra lead to strong constraints on the supernova explosion models.

  17. Dynamics of excess electrons in atomic and molecular clusters

    E-Print Network [OSTI]

    Young, Ryan Michael

    2011-01-01T23:59:59.000Z

    2.2 Femtosecond laser system Ultrafast pulses are generatedwith ultrafast lasers is that the laser pulse generationultrafast systems, everything which must sync to a laser pulse

  18. Title: Combined passive detection and ultrafast active imaging of cavitation events induced by short pulses of high intensity

    E-Print Network [OSTI]

    Boyer, Edmond

    1 Title: Combined passive detection and ultrafast active imaging of cavitation events induced by short pulses of high intensity ultrasound Authors: Jérôme GATEAU, Jean-François AUBRY, Mathieu PERNOT / INSERM, U979 / Université Denis Diderot, Paris VII Key words: single nucleation events, ultrafast active

  19. Electron-ion relaxation time dependent signal enhancement in ultrafast double-pulse laser-induced breakdown spectroscopy

    E-Print Network [OSTI]

    Harilal, S. S.

    Electron-ion relaxation time dependent signal enhancement in ultrafast double-pulse laser of collinear double-pulse compared to single-pulse ultrafast laser induced breakdown spectroscopy. Our results showed that the significant signal enhancement noticed in the double pulse scheme is strongly correlated

  20. Subnanometer-Scale Measurements of the Interaction of Ultrafast Soft X-Ray Free-Electron-Laser Pulses with Matter

    E-Print Network [OSTI]

    von der Linde, D.

    lengths greater than 3 A° . This experiment demonstrates that with intense ultrafast pulses, structuralSubnanometer-Scale Measurements of the Interaction of Ultrafast Soft X-Ray Free-Electron-Laser Pulses with Matter Stefan P. Hau-Riege,1,* Henry N. Chapman,1 Jacek Krzywinski,2 Ryszard Sobierajski,2

  1. Rabi oscillations of Morris-Shore transformed $N$-state systems by elliptically polarized ultrafast laser pulses

    E-Print Network [OSTI]

    Kim, Hyosub; Lee, Han-gyeol; Ahn, Jaewook

    2015-01-01T23:59:59.000Z

    We present an experimental investigation of ultrafast-laser driven Rabi oscillations of atomic rubidium. Since the broadband spectrum of an ultrafast laser pulse simultaneously couples all the electronic hyperfine transitions between the excited and ground states, the complex excitation linkages involved with the D1 or D2 transition are energy degenerate. Here, by applying the Morris-Shore transformation, it is shown that this multi-state system is reduced to a set of independent two-state systems and dark states. In experiments performed by ultrafast laser interactions of atomic rubidium in the strong interaction regime, we demonstrate that the ultrafast dynamics of the considered multi-state system is governed by a sum of at most two decoupled Rabi oscillations when this system interacts with ultrafast laser pulses of any polarization state. We further show the implication of this result to possible controls of photo-electron polarizations.

  2. Observation of off-Hugoniot shocked states with ultrafast time resolution

    SciTech Connect (OSTI)

    Armstrong, M; Crowhurst, J; Bastea, S; Zaug, J

    2010-02-23T23:59:59.000Z

    We apply ultrafast single shot interferometry to determine the pressure and density of argon shocked from up to 7.8 GPa static initial pressure in a diamond anvil cell. This method enables the observation of thermodynamic states distinct from those observed in either single shock or isothermal compression experiments, and the observation of ultrafast dynamics in shocked materials. We also present a straightforward method for interpreting ultrafast shock wave data which determines the index of refraction at the shock front, and the particle and shock velocities for shock waves in transparent materials. Based on these methods, we observe shocked thermodynamic states between the room temperature isotherm of argon and the shock adiabat of cryogenic argon at final shock pressures up to 28 GPa.

  3. Quantitative comparison of fuel spray images obtained using ultrafast coherent and incoherent double-pulsed illumination

    E-Print Network [OSTI]

    Purwar, Harsh; Idlahcen, Saïd; Rozé, Claude; Blaisot, Jean-Bernard; Ménard, Thibault

    2015-01-01T23:59:59.000Z

    We present a quantitative comparison between the high-pressure fuel spray images obtained experimentally using classical imaging with coherent and incoherent ultrafast illuminations recorded using a compatible CMOS camera. The ultrafast, incoherent illumination source was extracted from the supercontinuum generated by tightly focusing the femtosecond laser pulses in water. The average velocity maps computed using time-correlated image-pairs and spray edge complexity computed using the average curvature scale space maps are compared for the spray images obtained with the two illumination techniques and also for the numerically simulated spray using the coupled volume of fluid and level set method for interface tracking (direct numerical simulation or DNS). The spray images obtained with supercontinuum-derived, incoherent, ultrafast illumination are clearer, since the artifacts arising due to laser speckles and multiple diffraction effects are largely reduced and show a better correlation with the DNS results.

  4. Ultrafast time dynamics studies of periodic lattices with free electron laser radiation

    SciTech Connect (OSTI)

    Quevedo, W.; Busse, G.; Hallmann, J.; More, R.; Petri, M.; Rajkovic, I. [Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Goettingen (Germany); Krasniqi, F.; Rudenko, A. [Max Planck Advanced Study Group at CFEL, Notkestrasse 85, 22607 Hamburg (Germany); Tschentscher, T. [European XFEL GmbH, Albert-Einstein-Ring 19, 22671 Hamburg (Germany); Stojanovic, N.; Duesterer, S.; Treusch, R.; Tolkiehn, M. [HASYLAB at DESY, Notkestrasse 85, 22607 Hamburg (Germany); Techert, S. [Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Goettingen (Germany); Max Planck Advanced Study Group at CFEL, Notkestrasse 85, 22607 Hamburg (Germany)

    2012-11-01T23:59:59.000Z

    It has been proposed that radiation from free electron laser (FEL) at Hamburg (FLASH) can be used for ultrafast time-resolved x-ray diffraction experiments based on the near-infrared (NIR) pump/FEL probe scheme. Here, investigation probing the ultrafast structural dynamics of periodic nano-crystalline organic matter (silver behenate) with such a scheme is reported. Excitation with a femtosecond NIR laser leads to an ultrafast lattice modification which time evolution has been studied through the scattering of vacuum ultraviolet FEL pulses. The found effect last for 6 ps and underpins the possibility for studying nanoperiodic dynamics down to the FEL source time resolution. Furthermore, the possibility of extending the use of silver behenate (AgBh) as a wavelength and temporal calibration tool for experiments with soft x-ray/FEL sources is suggested.

  5. Isotopically Enriched Films and Nanostructures by Ultrafast Pulsed Laser Deposition

    SciTech Connect (OSTI)

    Peter Pronko

    2004-12-13T23:59:59.000Z

    This project involved a systematic study to apply newly discovered isotopic enrichment effects in laser ablation plumes to the fabrication of isotopically engineered thin films, superlattices, and nanostructures. The approach to this program involved using ultrafast lasers as a method for generating ablated plasmas that have preferentially structured isotopic content in the body of the ablation plasma plumes. In examining these results we have attempted to interpret the observations in terms of a plasma centrifuge process that is driven by the internal electro-magnetic fields of the plasma itself. The research plan involved studying the following phenomena in regard to the ablation plume and the isotopic mass distribution within it: (1) Test basic equations of steady state centrifugal motion in the ablation plasma. (2) Investigate angular distribution of ions in the ablation plasmas. (3) Examine interactions of plasma ions with self-generated magnetic fields. (3) Investigate ion to neutral ratios in the ablation plasmas. (5) Test concepts of plasma pumping. (6) Fabricate isotopically enriched nanostructures.

  6. Extension - Upgrading Methane Using Ultra-Fast Thermal Swing Adsorption

    SciTech Connect (OSTI)

    Anna Lee Tonkovich

    2008-08-11T23:59:59.000Z

    The need for cost effective technologies for upgrading coal mine methane to pipeline quality natural gas is becoming ever greater. The current work presents and investigates a new approach to reduce the impact of the most costly step in the conventional technology, nitrogen rejection. The proposed approach is based on the Velocys microchannel platform, which is being developed to commercialize compact and cost efficient chemical processing technology. For this separation, ultra fast thermal swing sorption is enabled by the very high rates of heat and mass transfer inherent in microchannel processing. In a first phase of the project solid adsorbents were explored. Feasibility of ultrafast thermal swing was demonstrated but the available adsorbents had insufficient differential methane capacity to achieve the required commercial economics. In a second phase, ionic liquids were adopted as absorbents of choice, and experimental work and economic analyses, performed to gauge their potential, showed promise for this novel alternative. Final conclusions suggest that a combination of a required cost target for ionic liquids or a methane capacity increase or a combination of both is required for commercialization.

  7. ULTRAFAST OUTFLOWS: GALAXY-SCALE ACTIVE GALACTIC NUCLEUS FEEDBACK

    SciTech Connect (OSTI)

    Wagner, A. Y.; Umemura, M. [Center for Computational Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8577 (Japan); Bicknell, G. V., E-mail: ayw@ccs.tsukuba.ac.jp [Research School of Astronomy and Astrophysics, Australian National University, ACT 2611 (Australia)

    2013-01-20T23:59:59.000Z

    We show, using global three-dimensional grid-based hydrodynamical simulations, that ultrafast outflows (UFOs) from active galactic nuclei (AGNs) result in considerable feedback of energy and momentum into the interstellar medium (ISM) of the host galaxy. The AGN wind interacts strongly with the inhomogeneous, two-phase ISM consisting of dense clouds embedded in a tenuous, hot, hydrostatic medium. The outflow floods through the intercloud channels, sweeps up the hot ISM, and ablates and disperses the dense clouds. The momentum of the UFO is primarily transferred to the dense clouds via the ram pressure in the channel flow, and the wind-blown bubble evolves in the energy-driven regime. Any dependence on UFO opening angle disappears after the first interaction with obstructing clouds. On kpc scales, therefore, feedback by UFOs operates similarly to feedback by relativistic AGN jets. Negative feedback is significantly stronger if clouds are distributed spherically rather than in a disk. In the latter case, the turbulent backflow of the wind drives mass inflow toward the central black hole. Considering the common occurrence of UFOs in AGNs, they are likely to be important in the cosmological feedback cycles of galaxy formation.

  8. An ultrafast phase-change logic device driven by melting processes

    E-Print Network [OSTI]

    Loke, D.; Skelton, J. M.; Wang, W. J.; Lee, T. H.; Zhao, R.; Chong, T. C.; Elliott, S. R.

    2014-09-02T23:59:59.000Z

    /device structures are developed with a higher number of resistance levels and resistance-level combinations (11,14). 6 The GST cells have been shown to exhibit ultra-fast Boolean algebraic operations via boosting the energy delivered by electrical-pulse... 1 Title An ultrafast phase-change logic device driven by melting processes Authors D. Loke,1,2,3 J. M. Skelton,1,4 W. J. Wang,5 T. H. Lee,1 R. Zhao,2 T. C. Chong,2,* S. R. Elliott,1,* Affiliations 1Department of Chemistry, University...

  9. A grazing incidence x-ray streak camera for ultrafast, single-shot measurements

    SciTech Connect (OSTI)

    Feng, Jun; Engelhorn, K.; Cho, B.I.; Lee, H.J.; Greaves, M.; Weber, C.P.; Falcone, R.W.; Padmore, H. A.; Heimann, P.A.

    2010-02-18T23:59:59.000Z

    An ultrafast x-ray streak camera has been realized using a grazing incidence reflection photocathode. X-rays are incident on a gold photocathode at a grazing angle of 20 degree and photoemitted electrons are focused by a large aperture magnetic solenoid lens. The streak camera has high quantum efficiency, 600fs temporal resolution, and 6mm imaging length in the spectral direction. Its single shot capability eliminates temporal smearing due to sweep jitter, and allows recording of the ultrafast dynamics of samples that undergo non-reversible changes.

  10. Nanoparticle size and morphology control using ultrafast laser induced forward transfer of Ni thin films

    SciTech Connect (OSTI)

    Murphy, Ryan D. [Applied Physics Program, University of Michigan, Ann Arbor, Michigan 48109 (United States)] [Applied Physics Program, University of Michigan, Ann Arbor, Michigan 48109 (United States); Abere, Michael J.; Schrider, Keegan J.; Yalisove, Steven M. [Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109 (United States)] [Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109 (United States); Torralva, Ben [Department of Atmospheric, Oceanic and Space Sciences, University of Michigan, Ann Arbor, Michigan 48109 (United States)] [Department of Atmospheric, Oceanic and Space Sciences, University of Michigan, Ann Arbor, Michigan 48109 (United States)

    2013-08-26T23:59:59.000Z

    We have developed a nanoparticle (NP) printing technique using Ni thin film lift-off from glass substrates after ultrafast irradiation in air. Unique interactions of ultrafast laser pulses with thin films allow for control over NP faceting and size distributions. Control is achieved by changing the laser fluence, film thickness, and film-substrate distance. We demonstrate 20 nm Ni film removal from substrates and rapid NP printing, with size distributions centered at a 6 nm diameter. When the Ni film thickness is lowered to 10 nm, NPs are printed with distributions peaked at a 2 nm diameter.

  11. Simultaneous investigation of ultrafast structural dynamics and transient electric field by sub-picosecond electron pulses

    SciTech Connect (OSTI)

    Li, Run-Ze; Zhu, Pengfei; Chen, Long; Chen, Jie, E-mail: jiec@sjtu.edu.cn, E-mail: jzhang1@sjtu.edu.cn; Sheng, Zheng-Ming; Zhang, Jie, E-mail: jiec@sjtu.edu.cn, E-mail: jzhang1@sjtu.edu.cn [Key Laboratory for Laser Plasmas (Ministry of Education) and Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China); Cao, Jianming [Key Laboratory for Laser Plasmas (Ministry of Education) and Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China); Physics Department and National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310 (United States)

    2014-05-14T23:59:59.000Z

    The ultrafast structure dynamics and surface transient electric field, which are concurrently induced by laser excited electrons of an aluminum nanofilm, have been investigated simultaneously by the same transmission electron diffraction patterns. These two processes are found to be significantly different and distinguishable by tracing the time dependent changes of electron diffraction and deflection angles, respectively. This study also provides a practical means to evaluate simultaneously the effect of transient electric field during the study of structural dynamics under low pump fluence by transmission ultrafast electron diffraction.

  12. Magnetically-Driven Accretion-Disk Winds and Ultra-Fast Outflows in PG1211+143

    E-Print Network [OSTI]

    Fukumura, Keigo; Kazanas, Demosthenes; Shrader, Chris; Behar, Ehud; Contopoulos, Ioannis

    2015-01-01T23:59:59.000Z

    We present a study of X-ray ionization of magnetohydrodynamic (MHD) accretion-disk winds in an effort to constrain the physics underlying the highly-ionized ultra-fast outflows (UFOs) inferred by X-ray absorbers often detected in various sub-classes of Seyfert active galactic nuclei (AGNs). Our primary focus is to show that magnetically-driven outflows are indeed physically plausible candidates for the observed outflows accounting for the AGN absorption properties of the present X-ray spectroscopic observations. Employing a stratified MHD wind launched across the entire AGN accretion disk, we calculate its X-ray ionization and the ensuing X-ray absorption line spectra. Assuming an appropriate ionizing AGN spectrum, we apply our MHD winds to model the absorption features in an {\\it XMM-Newton}/EPIC spectrum of the narrow-line Seyfert, \\pg. We find, through identifying the detected features with Fe K$\\alpha$ transitions, that the absorber has a characteristic ionization parameter of $\\log (\\xi_c [erg~cm~s$^{-1}...

  13. Semiclassical molecular dynamics simulations of ultrafast photodissociation dynamics associated with the Chappuis band of ozone

    E-Print Network [OSTI]

    Miller, William H.

    with the Chappuis band of ozone Victor S. Batista and William H. Millera) Department of Chemistry, University A ) of ozone following photoexcitation of the molecule in the gas phase with visible light. Our algorithm and recurrence events, as well as an interpretation of experimental studies of the Chappuis band of ozone

  14. H. Ihee et al., "Ultrafast X-ray diffraction of transient molecular structures in solution."

    E-Print Network [OSTI]

    Ihee, Hyotcherl

    -consistent reaction field (SCRF) theory. The SCIPCM (S9) model, which allows geometry optimization at the HF and DFT

  15. Ultrafast studies of photodissociation in solution: Dissociation, recombination and relaxation

    SciTech Connect (OSTI)

    King, J.C.

    1995-05-01T23:59:59.000Z

    Photodissociation of M(CO){sub 6} (M=Cr,Mo,W) and the formation of solvated M(CO){sub 5}{center_dot}S complex was studied in cyclohexane; rate-limiting step is vibrational energy relaxation from the new bond to the solvent. For both M=Cr and Mo, the primary relaxation occurs in 18 ps; for Cr, there is an additional vibrational relaxation (150 ps time scale) of a CO group poorly coupled to other modes. Relaxation of M=W occurs in 42 ps; several possible mechanisms for the longer cooling are discussed. Vibrational relaxation is also investigated for I{sub 2}{sup -} and IBr{sup {minus}} in nonpolar and slightly polar solvents. Attempts were made to discover the mechanism for the fast energy transfer in nonpolar solvent. The longer time scale dynamics of I{sub 3}{sup {minus}} and IBr{sub 2}{sup {minus}} were also studied; both formed a metastable complex following photodissociation and 90-95% return to ground state in 100 ps, implying a barrier to recombination of 4.3 kcal/mol and a barrier to escape of {ge}5.5 kcal/mol. The more complex photochemistry of M{sub 3}(CO){sub 12} (M=Fe,Ru) is also investigated, using visible and ultraviolet radiations, dissociation, geminate recombination, vibrational relaxation, and bridging structures and their reactions were studied. Attempts were made to extend ultrafast spectroscopy into the mid-infrared, but signal-to-noise was poor.

  16. Coherent matter waves for ultrafast laser pulse characterization M. Winter, M. Wollenhaupt, T. Baumert *

    E-Print Network [OSTI]

    Peinke, Joachim

    Coherent matter waves for ultrafast laser pulse characterization M. Winter, M. Wollenhaupt, T for the characterization of ultrashort laser pulses using coherent matter waves is demonstrated. We emphasize the anal- ogy theoretically and experimentally and is the basis for our laser pulse character- ization technique. We use

  17. Three envelope approach for ultrafast pulse characterization in a pump-probe experiment

    E-Print Network [OSTI]

    Three envelope approach for ultrafast pulse characterization in a pump-probe experiment Balakishore of temporally identical ultrashort pulses at the focal point in a pump-probe experiment for potential use, fundamental, and second harmonic spectra, combined with an error minimization pulse retrieval scheme

  18. Broadband conversion in an Yb:KYW-pumped ultrafast optical parametric oscillator with a long

    E-Print Network [OSTI]

    Broadband conversion in an Yb:KYW-pumped ultrafast optical parametric oscillator with a long-infrared pulses at 3.5-µm from an optical parametric oscillator incorporating a 25- mm MgO:PPLN crystal and synchronously-pumped by chirped pulses from a fiber-amplified Yb:KYW laser. A long nonlinear crystal permits

  19. DEVELOPMENT OF NEW MID-INFRARED ULTRAFAST LASER SOURCES FOR COMPACT COHERENT X-RAY SOURCES

    SciTech Connect (OSTI)

    Sterling Backus

    2012-05-14T23:59:59.000Z

    In this project, we proposed to develop laser based mid-infrared lasers as a potentially robust and reliable source of ultrafast pulses in the mid-infrared region of the spectrum, and to apply this light source to generating bright, coherent, femtosecond-to-attosecond x-ray beams.

  20. Ultrafast Material Science Probed Using Coherent X-ray Pulses from High-Harmonic

    E-Print Network [OSTI]

    Aeschlimann, Martin

    Chapter 7 Ultrafast Material Science Probed Using Coherent X-ray Pulses from High science have made it possible to generate x-ray pulses at the femto- and attosecond frontiers using either-ray pulses paves the way for a completely new generation of experiments that can capture the coupled dynamics

  1. OPTI-583: Computational Optics I: Ultrafast pulses and strong-field light-matter interactions.

    E-Print Network [OSTI]

    Arizona, University of

    OPTI-583: Computational Optics I: Ultrafast pulses and strong-field light-matter interactions. Time-power femtosecond pulses. Prerequisites: Knowledge of basic electromagnetic theory (e.g. Phys-241). While previous that govern the interaction of ultrashort pulses with var- ious media, and the Numerical methods track

  2. Internal friction in the ultrafast folding of the tryptophan cage q Linlin Qiu 1

    E-Print Network [OSTI]

    Hagen, Stephen J.

    Internal friction in the ultrafast folding of the tryptophan cage q Linlin Qiu 1 , Stephen J. Hagen is a diffusional process, and the speed of folding is controlled by the frictional forces that act important source of friction in folding reactions. By contrast, our studies of the folding dynamics

  3. Ultra-Fast Absorption of Amorphous Pure Drug Aerosols Via Deep Lung Inhalation

    E-Print Network [OSTI]

    Rabinowitz, Joshua D.

    Ultra-Fast Absorption of Amorphous Pure Drug Aerosols Via Deep Lung Inhalation JOSHUA D. RABINOWITZ inhalation. The speed of pulmonary drug absorption depends on the site of aerosol deposition within the lung incorporating this thermal aerosol technology, and its application to the delivery of alprazolam, an anti

  4. Ultrafast absorber saturation process and short pulse formation in injection lasers

    E-Print Network [OSTI]

    Buller, Gerald S.

    Ultrafast absorber saturation process and short pulse formation in injection lasers S. V. Zaitsev 1998 The nature of lasing threshold in passively Q-switched GaAs/AlGaAs lasers with saturable absorbers formed by heavy ion implantation is investigated in this article. After studying various laser

  5. Optical Deflection and Temporal Characterization of an Ultrafast Laser-Produced Electron Beam

    E-Print Network [OSTI]

    Umstadter, Donald

    Optical Deflection and Temporal Characterization of an Ultrafast Laser-Produced Electron Beam show that the optical pulse with a0 0:5 imparts momentum to the electron beam, causing it to deflect optically driven x-ray sources based on nonlinear Thomson scattering [3­5]. A finite optical pulse imparts

  6. Ultrafast shift and injection currents observed in wurtzite semiconductors via emitted terahertz radiation

    E-Print Network [OSTI]

    Van Driel, Henry M.

    Ultrafast shift and injection currents observed in wurtzite semiconductors via emitted terahertz; published online 18 November 2005 Shift and injection currents are generated in the wurtzite semiconductors in the wurtzite structure. The largest shift currents are generated along the optical axis for light polarized

  7. hal-00137243,version1-19Mar2007 High shock release in ultrafast laser irradiated metals

    E-Print Network [OSTI]

    Boyer, Edmond

    hal-00137243,version1-19Mar2007 High shock release in ultrafast laser irradiated metals: Scenario matter exposed to subpicosecond near infrared pulsed laser radiation. We point out to the role of strong of material exceeding the specific energy required for melting is reported for copper and aluminum

  8. Water Dynamics in Salt Solutions Studied with Ultrafast Two-Dimensional Infrared (2D IR)

    E-Print Network [OSTI]

    Fayer, Michael D.

    Water Dynamics in Salt Solutions Studied with Ultrafast Two-Dimensional Infrared (2D IR RECEIVED ON FEBRUARY 3, 2009 C O N S P E C T U S Water is ubiquitous in nature, but it exists as pure water infrequently. From the ocean to biology, water molecules interact with a wide variety of dissolved species

  9. Water at the Surfaces of Aligned Phospholipid Multibilayer Model Membranes Probed with Ultrafast Vibrational

    E-Print Network [OSTI]

    Fayer, Michael D.

    Water at the Surfaces of Aligned Phospholipid Multibilayer Model Membranes Probed with Ultrafast@stanford.edu Abstract: The dynamics of water at the surface of artificial membranes composed of aligned multibilayers pump-probe spectroscopy. The experiments are performed at various hydration levels, x ) 2 - 16 water

  10. Analysis of the Ultra-fast Switching Dynamics in a Hybrid MOSFET/Driver

    SciTech Connect (OSTI)

    Tang, T.; Burkhart, C.; /SLAC

    2011-08-17T23:59:59.000Z

    The turn-on dynamics of a power MOSFET during ultra-fast, {approx} ns, switching are discussed in this paper. The testing was performed using a custom hybrid MOSFET/Driver module, which was fabricated by directly assembling die-form components, power MOSFET and drivers, on a printed circuit board. By using die-form components, the hybrid approach substantially reduces parasitic inductance, which facilitates ultra-fast switching. The measured turn on time of the hybrid module with a resistive load is 1.2 ns with an applied voltage of 1000 V and drain current of 33 A. Detailed analysis of the switching waveforms reveals that switching behavior must be interpreted differently in the ultra-fast regime. For example, the gate threshold voltage to turn on the device is observed to increase as the switching time decreases. Further analysis and simulation of MOSFET switching behavior shows that the minimum turn on time scales with the product of the drain-source on resistance and drain-source capacitance, R{sub DS(on)}C{sub OSS}. This information will be useful in power MOSFET selection and gate driver design for ultra-fast switching applications.

  11. Module Title: Solid state and ultrafast lasers Module Code: OPTO6002

    E-Print Network [OSTI]

    Anderson, Jim

    and techniques Heat generation and thermal management Power scaling strategies (cladding-pumping, MOP calculations on the operating parameter and output parameters of a wide variety of solid state and ultrafast efficiency, output power, gain Laser modes and resonator design Pump sources, pump delivery and coupling

  12. Generation of sub-30-fs microjoule mid-infrared pulses for ultrafast vibrational

    E-Print Network [OSTI]

    Borguet, Eric

    compression. http://dx.doi.org/10.1364/OL.38.005008 Understanding ultrafast interactions in solids and con]. The dispersion properties of certain nonlinear optical materials, such as potassium titanyl phosphate (KTP), lithium niobate (LNB), potassium niobate (KNB), and periodically poled stoichiometric lithium tantalate

  13. Ultrafast Proton Shuttling in Psammocora Cyan Fluorescent Protein John T. M. Kennis,*,

    E-Print Network [OSTI]

    van Stokkum, Ivo

    Ultrafast Proton Shuttling in Psammocora Cyan Fluorescent Protein John T. M. Kennis,*, Ivo H. M-state proton transfer (ESPT) reactions. Recently, a novel cyan fluorescent protein (CFP) termed psamFP488 vicinity to the chromophore to act as a proton acceptor. Our findings support a model where unusually fast

  14. Ultrafast MR Grid-Tagging Sequence for Assessment of Local Mechanical Properties of the Lungs

    E-Print Network [OSTI]

    Napadow, Vitaly

    Ultrafast MR Grid-Tagging Sequence for Assessment of Local Mechanical Properties of the Lungs Qun in MR imaging of lung parenchyma. In this study, a fast MR grid-tagging technique is described deformation of the lung. Quantitative analysis of the data shows that this method is capable of assessing

  15. Dynamics of Hemoglobin in Human Erythrocytes and in Solution: Influence of Viscosity Studied by Ultrafast

    E-Print Network [OSTI]

    Fayer, Michael D.

    Dynamics of Hemoglobin in Human Erythrocytes and in Solution: Influence of Viscosity Studied by Ultrafast Vibrational Echo Experiments Brian L. McClain, Ilya J. Finkelstein, and M. D. Fayer* Contribution experiments are used to measure the vibrational dephasing of the CO stretching mode of hemoglobin-CO (Hb

  16. Dynamics of the folded and unfolded villin headpiece (HP35) measured with ultrafast

    E-Print Network [OSTI]

    Fayer, Michael D.

    Dynamics of the folded and unfolded villin headpiece (HP35) measured with ultrafast 2D IR in the folded configuration. The dynamics of the folded HP35-ðCNÞ2 are compared to that of the guanidine to differentiate the peptide dynamic contributions to the observables from those of the water solvent. Because

  17. Ultrafast high-pressure AC electro-osmotic pumps for portable biomedical microfluidics

    E-Print Network [OSTI]

    Bazant, Martin Z.

    Ultrafast high-pressure AC electro-osmotic pumps for portable biomedical microfluidics Chien details the development of an integrated AC electro-osmotic (ACEO) microfluidic pump for dilute (100 mM) biological solutions in separate microfluidic devices, with potential applications in portable

  18. All-optical fiber-based devices for ultrafast amplitude jitter magnification

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    All-optical fiber-based devices for ultrafast amplitude jitter magnification Charles-Henri Hage-intercept PC with 0 jitter will increase [3]. We first jitter of a 10-GHz picosecond pulse train delivered by an actively mode-locked erbium doped fiber laser

  19. Neuroglobin dynamics observed with ultrafast 2D-IR vibrational echo spectroscopy

    E-Print Network [OSTI]

    Fayer, Michael D.

    Neuroglobin dynamics observed with ultrafast 2D-IR vibrational echo spectroscopy Haruto Ishikawa Contributed by Michael D. Fayer, August 15, 2007 (sent for review July 25, 2007) Neuroglobin (Ngb), a protein energy minimum. myoglobin mutants protein dynamics energy landscape Neuroglobin (Ngb) is a recently

  20. HARMONIC CASCADE FEL DESIGNS FOR LUX, A FACILTY FOR ULTRAFAST X-RAY SCIENCE

    E-Print Network [OSTI]

    Wurtele, Jonathan

    HARMONIC CASCADE FEL DESIGNS FOR LUX, A FACILTY FOR ULTRAFAST X-RAY SCIENCE J. Corlett, W. Fawley. We also discuss lattice considerations pertinent to harmonic cascade FELs, somesensitivity studies. While much of this effort has been concentrated upon SASE-based FEL's, there is an alternative "harmonic

  1. Ultrafast Structural Dynamics Inside Planar Phospholipid Multibilayer Model Cell Membranes Measured with 2D IR

    E-Print Network [OSTI]

    Fayer, Michael D.

    Ultrafast Structural Dynamics Inside Planar Phospholipid Multibilayer Model Cell Membranes Measured diffusion caused by the structural dynamics of the membrane from 200 fs to 200 ps as a function structure and an abrupt change in dynamics at 35% cholesterol. The dynamics are independent of cholesterol

  2. Ultrafast optical nonlinearity in poly,,methylmethacrylate...-TiO2 nanocomposites

    E-Print Network [OSTI]

    Wei, Ji

    -quality, transparent films consisting of polymer-TiO2 hybrid nanocomposites, and on their linear optical properties.3Ultrafast optical nonlinearity in poly,,methylmethacrylate...-TiO2 nanocomposites H. I. Elim and W nanocomposites, which are synthesized by a simple technique of in-situ sol-gel/polymerization. The best figures

  3. Shock-wave generation in transparent media from ultra-fast lasers R. Bernath*a

    E-Print Network [OSTI]

    Van Stryland, Eric

    Shock-wave generation in transparent media from ultra-fast lasers R. Bernath*a , C. G. Browna , J a harmonic of the pump laser frequency. Experiments also include burst-mode operation, where a train of ultra. Aspiotisa , M. Fishera , & M. Richardsona a Laser Plasma Laboratory, College of Optics & Photonics: CREOL

  4. IOP PUBLISHING JOURNAL OF PHYSICS B: ATOMIC, MOLECULAR AND OPTICAL PHYSICS J. Phys. B: At. Mol. Opt. Phys. 43 (2010) 194004 (16pp) doi:10.1088/0953-4075/43/19/194004

    E-Print Network [OSTI]

    Kling, Matthias

    2010-01-01T23:59:59.000Z

    experiments A Rudenko1, Y H Jiang2, M Kurka2, K U K¨uhnel2, L Foucar1, O Herrwerth3, M Lezius3, M F Kling3, C) 194004 A Rudenko et al matter have become one of the hottest topics in atomic, molecular and optical

  5. Physics Division annual report - 1998

    SciTech Connect (OSTI)

    NONE

    1999-09-07T23:59:59.000Z

    Summaries are given of progress accomplished for the year in the following areas: (1) Heavy-Ion Nuclear Physics Research; (2) Operation and Development of Atlas; (3) Medium-Energy Nuclear Physics Research; (4) Theoretical Physics Research; and (5) Atomic and Molecular Physics Research.

  6. Long-term stable timing distribution of an ultrafast optical pulse train over multiple fiber links with polarization maintaining output

    E-Print Network [OSTI]

    Cox, Jonathan A.

    The distribution of an ultrafast optical pulse train over multiple fiber links with long-term stable timing precision within 2 femtoseconds rms is accomplished by integrating a polarization maintaining output with 300 meter ...

  7. Molecular dynamics of excited state intramolecular proton transfer: 3-hydroxyflavone in solution

    SciTech Connect (OSTI)

    Bellucci, Michael A.; Coker, David F. [Department of Chemistry, Boston University, 590 Commonwealth Avenue, Boston, Massachusetts 02215 (United States)

    2012-05-21T23:59:59.000Z

    The ultrafast enol-keto photoisomerization in the lowest singlet excited state of 3-hydroxyflavone is investigated using classical molecular dynamics in conjunction with empirical valence bond (EVB) potentials for the description of intramolecular interactions, and a molecular mechanics and variable partial charge model, dependent on transferring proton position, for the description of solute-solvent interactions. A parallel multi-level genetic program was used to accurately fit the EVB potential energy surfaces to high level ab initio data. We have studied the excited state intramolecular proton transfer (ESIPT) reaction in three different solvent environments: methylcyclohexane, acetonitrile, and methanol. The effects of the environment on the proton transfer time and the underlying mechanisms responsible for the varied time scales of the ESIPT reaction rates are analyzed. We find that simulations with our EVB potential energy surfaces accurately reproduce experimentally determined reaction rates, fluorescence spectra, and vibrational frequency spectra in all three solvents. Furthermore, we find that the ultrafast ESIPT process results from a combination of ballistic transfer, and intramolecular vibrational redistribution, which leads to the excitation of a set of low frequency promoting vibrational modes. From this set of promoting modes, we find that an O-O in plane bend and a C-H out of plane bend are present in all three solvents, indicating that they are fundamental to the ultrafast proton transfer. Analysis of the slow proton transfer trajectories reveals a solvent mediated proton transfer mechanism, which is diffusion limited.

  8. Hot-electron-driven charge transfer processes on O2 Pt,,111... surface probed by ultrafast extreme-ultraviolet pulses

    E-Print Network [OSTI]

    Bauer, Michael

    it with an ultrafast laser pulse, charge transfer induced changes in the platinum-oxygen bond were observedHot-electron-driven charge transfer processes on O2 Ã?Pt,,111... surface probed by ultrafast extreme-ultraviolet pulses C. Lei,1, * M. Bauer,2 K. Read,1 R. Tobey,1 Y. Liu,3 T. Popmintchev,1 M. M. Murnane,1 and H. C

  9. A novel ultra-fast parallel algorithm for image compression using semi-orthogonal spline boundary wavelets

    E-Print Network [OSTI]

    Mishra, Deepam

    1995-01-01T23:59:59.000Z

    A NOVEL ULTRA-FAST PARALLEL ALGORITHM FOR IMAGE COMPRESSION USING SEMI-ORTHOGONAL SPLINE BOUNDARY WAVELETS A Thesis by DEEPAM MISHRA Submitted to the Office of Graduate Studies of Texas ARM University in partial fulfillment... Yurt tps (Member) A. D. P tton (Head of D artment) December 1995 Major Subject: Electrical Engineering 111 ABSTRACT A Novel Ultra-Fast Parallel Image Compression Algorithm Using Spline Boundary Wavelets. (December 1995) Deepam Mishra, B. Tech...

  10. Upgrading Methane Using Ultra-Fast Thermal Swing Adsorption

    SciTech Connect (OSTI)

    Anna Lee Tonkovich

    2004-07-01T23:59:59.000Z

    The purpose of this project is to design and demonstrate an approach to upgrade low-BTU methane streams from coal mines to pipeline-quality natural gas. The objective of Phase I of the project was to assess the technical feasibility and cost of upgrading low-BTU methane streams using ultra-fast thermal swing adsorption (TSA) using Velocys modular microchannel process technology. The objective of Phase II is to demonstrate the process at the bench scale. The project is on schedule and on budget. A technical and economic feasibility assessment was completed in Task 3. The proposed Velocys technology appears feasible for the methane upgrading market. Evaluated categories include adsorbent selection, rapid-cycle valve selection, microchannel manufacturability assessment, and system design and cost. The selected adsorbent, granular microporous carbon from either Barnaby-Sutcliffe or Calgon, experimentally demonstrated sufficient methane capacity under differential temperature at 100 pounds per square inch gauge. Several valve options were identified, including candidates that can operate millions of cycles between refurbishment. The microchannel adsorber and desorber designs were made using internal Velocys manufacturability standards, and the associated costs are acceptable as included with the complete nitrogen rejection unit (NRU) cost projection. A system design and cost estimate was completed for the NRU section of the methane upgrading system. As integrated into the complete system, the cost is in line with the market requirement. The system has six main unit operations: feed compressor, dehydration unit, nitrogen rejection unit, deoxygenator, carbon dioxide scrubber, and a sales compressor. The NRU is the focus of the development program, and a bench-scale demonstration will be initiated in the next fiscal year. The Velocys NRU system targets producing methane with greater than 96% purity and at least 90% recovery for final commercial operation. A preliminary cost analysis of the methane upgrading system, including the Velocys NRU, suggests that costs below $2.00 per million (MM) BTU methane may be achieved. The cost for a conventional methane upgrading system is well above $2.30 per MM BTU, as benchmarked in an Environmental Protection Agency study.

  11. Ultrafast Laser Diagnostics for Energetic-Material Ignition Mechanisms: Tools for Physics-Based Model Development

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742EnergyOnItem Not FoundInformation DOEInformation Summary Big*Thee n0738F4-19513 Unlimited

  12. Journal of Physics B: Atomic, Molecular and Optical Physics J. Phys. B: At. Mol. Opt. Phys. 47 (2014) 075301 (12pp) doi:10.1088/0953-4075/47/7/075301

    E-Print Network [OSTI]

    Gammal, Arnaldo

    for the analysis of such condensates [4]. The long-range and anisotropic character of the DDI leads to new physical (2014) 075301 (12pp) doi:10.1088/0953-4075/47/7/075301 Bright solitons in Bose­Einstein condensates-dimensional model of a bosonic gas of particles carrying collinear dipole moments which are induced by an external

  13. Ultrafast Power Processor for Smart Grid Power Module Development

    SciTech Connect (OSTI)

    MAITRA, ARINDAM [EPRI] [EPRI; LITWIN, RAY [EPRI] [EPRI; lai, Jason [Enertronics] [Enertronics; Syracuse, David [Silicon Power] [Silicon Power

    2012-12-30T23:59:59.000Z

    This project’s goal was to increase the switching speed and decrease the losses of the power semiconductor devices and power switch modules necessary to enable Smart Grid energy flow and control equipment such as the Ultra-Fast Power Processor. The primary focus of this project involves exploiting the new silicon-based Super-GTO (SGTO) technology and build on prototype modules already being developed. The prototype super gate-turn-off thyristor (SGTO) has been tested fully under continuously conducting and double-pulse hard-switching conditions for conduction and switching characteristics evaluation. The conduction voltage drop measurement results indicate that SGTO has excellent conduction characteristics despite inconsistency among some prototype devices. Tests were conducted with two conditions: (1) fixed gate voltage and varying anode current condition, and (2) fixed anode current and varying gate voltage condition. The conduction voltage drop is relatively a constant under different gate voltage condition. In terms of voltage drop as a function of the load current, there is a fixed voltage drop about 0.5V under zero current condition, and then the voltage drop is linearly increased with the current. For a 5-kV voltage blocking device that may operate under 2.5-kV condition, the projected voltage drop is less than 2.5 V under 50-A condition, or 0.1%. If the device is adopted in a converter operating under soft-switching condition, then the converter can achieve an ultrahigh efficiency, typically above 99%. The two-pulse switching test results indicate that SGTO switching speed is very fast. The switching loss is relatively low as compared to that of the insulated-gate-bipolar-transistors (IGBTs). A special phenomenon needs to be noted is such a fast switching speed for the high-voltage switching tends to create an unexpected C?dv/dt current, which reduces the turn-on loss because the dv/dt is negative and increases the turn-off loss because the dv/dt is positive. As a result, the turn-on loss at low current is quite low, and the turn-off loss at low current is relatively high. The phenomenon was verified with junction capacitance measurement along with the dv/dt calculation. Under 2-kV test condition, the turn-on and turn-off losses at 25-A is about 3 and 9 mJ, respectively. As compared to a 4.5-kV, 60-A rated IGBT, which has turn-on and turn-off losses about 25 and 20 mJ under similar test condition, the SGTO shows significant switching loss reduction. The switching loss depends on the switching frequency, but under hard-switching condition, the SGTO is favored to the IGBT device. The only concern is during low current turn-on condition, there is a voltage bump that can translate to significant power loss and associated heat. The reason for such a current bump is not known from this study. It is necessary that the device manufacturer perform though test and provide the answer so the user can properly apply SGTO in pulse-width-modulated (PWM) converter and inverter applications.

  14. Ultrafast Charge Separation and Nongeminate Electron-Hole Recombination in Organic Photovoltaics

    E-Print Network [OSTI]

    Samuel L Smith; Alex W Chin

    2014-06-04T23:59:59.000Z

    The mechanism of electron-hole separation in organic solar cells is currently hotly debated. Recent experimental work suggests that these charges can separate on extremely short timescales (<100 fs). This can be understood in terms of delocalised transport within fullerene aggregates, which is thought to emerge on short timescales before vibronic relaxation induces polaron formation. However, in the optimal heterojunction morphology, electrons and holes will often re-encounter each other before reaching the electrodes. If such charges trap and cannot separate, then device efficiency will suffer. Here we extend the theory of ultrafast charge separation to incorporate polaron formation, and find that the same delocalised transport used to explain ultrafast charge separation can account for the suppression of nongeminate recombination in the best devices.

  15. Time-domain sampling of x-ray pulses using an ultrafast sample response

    SciTech Connect (OSTI)

    Gaal, P.; Shayduk, R. [Helmholtz-Zentrum Berlin fuer Materialien und Energie GmbH, Wilhelm-Conrad-Roentgen Campus, BESSY II, Albert-Einstein-Str. 15, 12489 Berlin (Germany); Schick, D.; Herzog, M.; Bojahr, A.; Goldshteyn, J.; Navirian, H. A.; Leitenberger, W. [Institut fuer Physik und Astronomie, Universitaet Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam (Germany); Vrejoiu, I. [Max-Planck-Institut fuer Mikrostrukturphysik, Weinberg 2, 06120 Halle (Germany); Khakhulin, D.; Wulff, M. [European Synchrotron Radiation Facility (ESRF), 6 rue Jules Horowitz, 38000 Grenoble (France); Bargheer, M. [Helmholtz-Zentrum Berlin fuer Materialien und Energie GmbH, Wilhelm-Conrad-Roentgen Campus, BESSY II, Albert-Einstein-Str. 15, 12489 Berlin (Germany); Institut fuer Physik und Astronomie, Universitaet Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam (Germany)

    2012-12-10T23:59:59.000Z

    We employ the ultrafast response of a 15.4 nm thin SrRuO{sub 3} layer grown epitaxially on a SrTiO{sub 3} substrate to perform time-domain sampling of an x-ray pulse emitted from a synchrotron storage ring. Excitation of the sample with an ultrashort laser pulse triggers coherent expansion and compression waves in the thin layer, which turn the diffraction efficiency on and off at a fixed Bragg angle during 5 ps. This is significantly shorter than the duration of the synchrotron x-ray pulse of 100 ps. Cross-correlation measurements of the ultrafast sample response and the synchrotron x-ray pulse allow to reconstruct the x-ray pulse shape.

  16. Department of Biological, Chemical and Physical Sciences Department of Biological, Chemical and Physical Sciences

    E-Print Network [OSTI]

    Saniie, Jafar

    ; and elementary particle physics, acceler- ator and plasma physics, condensed-matter physics, bio- logical physics for Accelerator and Particle Physics Center for the Molecular Study of Soft and Condensed Matter Research and particle physics are active. Collabo- rative programs are carried on with Fermi National Ac- celerator

  17. Time of flight emission spectroscopy of laser produced nickel plasma: Short-pulse and ultrafast excitations

    SciTech Connect (OSTI)

    Smijesh, N.; Chandrasekharan, K. [Laser and Nonlinear Optics Laboratory, Department of Physics, National Institute of Technology Calicut, Calicut 673601 (India); Joshi, Jagdish C.; Philip, Reji, E-mail: reji@rri.res.in [Ultrafast and Nonlinear Optics Lab, Light and Matter Physics Group, Raman Research Institute, Bangalore 560080 (India)

    2014-07-07T23:59:59.000Z

    We report the experimental investigation and comparison of the temporal features of short-pulse (7?ns) and ultrafast (100 fs) laser produced plasmas generated from a solid nickel target, expanding into a nitrogen background. When the ambient pressure is varied in a large range of 10{sup ?6?}Torr to 10{sup 2?}Torr, the plume intensity is found to increase rapidly as the pressure crosses 1?Torr. Time of flight (TOF) spectroscopy of emission from neutral nickel (Ni I) at 361.9?nm (3d{sup 9}({sup 2}D) 4p ? 3d{sup 9}({sup 2}D) 4s transition) reveals two peaks (fast and slow species) in short-pulse excitation and a single peak in ultrafast excitation. The fast and slow peaks represent recombined neutrals and un-ionized neutrals, respectively. TOF emission from singly ionized nickel (Ni II) studied using the 428.5?nm (3p{sup 6}3d{sup 8}({sup 3}P) 4s? 3p{sup 6}3d{sup 9} 4s) transition shows only a single peak for either excitation. Velocities of the neutral and ionic species are determined from TOF measurements carried out at different positions (i.e., at distances of 2?mm and 4?mm, respectively, from the target surface) on the plume axis. Measured velocities indicate acceleration of neutrals and ions, which is caused by the Coulomb pull of the electrons enveloping the plume front in the case of ultrafast excitation. Both Coulomb pull and laser-plasma interaction contribute to the acceleration in the case of short-pulse excitation. These investigations provide new information on the pressure dependent temporal behavior of nickel plasmas produced by short-pulse and ultrafast laser pulses, which have potential uses in applications such as pulsed laser deposition and laser-induced nanoparticle generation.

  18. DeepNet: An Ultrafast Neural Learning Code for Seismic Imaging

    SciTech Connect (OSTI)

    Barhen, J.; Protopopescu, V.; Reister, D.

    1999-07-10T23:59:59.000Z

    A feed-forward multilayer neural net is trained to learn the correspondence between seismic data and well logs. The introduction of a virtual input layer, connected to the nominal input layer through a special nonlinear transfer function, enables ultrafast (single iteration), near-optimal training of the net using numerical algebraic techniques. A unique computer code, named DeepNet, has been developed, that has achieved, in actual field demonstrations, results unattainable to date with industry standard tools.

  19. Ablation experiment and threshold calculation of titanium alloy irradiated by ultra-fast pulse laser

    SciTech Connect (OSTI)

    Zheng, Buxiang; Jiang, Gedong; Wang, Wenjun, E-mail: wenjunwang@mail.xjtu.edu.cn; Wang, Kedian; Mei, Xuesong [School of Mechanical Engineering, Xi'an Jiaotong University, No. 28, Xianning Westroad, Xi'an 710049 (China) [School of Mechanical Engineering, Xi'an Jiaotong University, No. 28, Xianning Westroad, Xi'an 710049 (China); State Key Laboratory for Manufacturing Systems Engineering, Xi'an Jiaotong University, Xi'an 710054 (China)

    2014-03-15T23:59:59.000Z

    The interaction between an ultra-fast pulse laser and a material's surface has become a research hotspot in recent years. Micromachining of titanium alloy with an ultra-fast pulse laser is a very important research direction, and it has very important theoretical significance and application value in investigating the ablation threshold of titanium alloy irradiated by ultra-fast pulse lasers. Irradiated by a picosecond pulse laser with wavelengths of 1064 nm and 532 nm, the surface morphology and feature sizes, including ablation crater width (i.e. diameter), ablation depth, ablation area, ablation volume, single pulse ablation rate, and so forth, of the titanium alloy were studied, and their ablation distributions were obtained. The experimental results show that titanium alloy irradiated by a picosecond pulse infrared laser with a 1064 nm wavelength has better ablation morphology than that of the green picosecond pulse laser with a 532 nm wavelength. The feature sizes are approximately linearly dependent on the laser pulse energy density at low energy density and the monotonic increase in laser pulse energy density. With the increase in energy density, the ablation feature sizes are increased. The rate of increase in the feature sizes slows down gradually once the energy density reaches a certain value, and gradually saturated trends occur at a relatively high energy density. Based on the linear relation between the laser pulse energy density and the crater area of the titanium alloy surface, and the Gaussian distribution of the laser intensity on the cross section, the ablation threshold of titanium alloy irradiated by an ultra-fast pulse laser was calculated to be about 0.109 J/cm{sup 2}.

  20. Precision lifetime measurements of a single trapped ion with ultrafast laser pulses D. L. Moehring,* B. B. Blinov, D. W. Gidley, R. N. Kohn, Jr., M. J. Madsen, T. D. Sanderson, R. S. Vallery, and C. Monroe

    E-Print Network [OSTI]

    Blinov, Boris

    Precision lifetime measurements of a single trapped ion with ultrafast laser pulses D. L. Moehring and ultrafast laser technologies, the ion is excited with picosecond laser pulses from a mode-locked laser excited state lifetime of order nanoseconds by an ultrafast laser pulse duration of order picoseconds

  1. Multidiagnostic analysis of ultrafast laser ablation of metals with pulse pair irradiation

    SciTech Connect (OSTI)

    Amoruso, S.; Bruzzese, R. [Dipartimento di Scienze Fisiche, Universita degli Studi di Napoli Federico II, Complesso Universitario di Monte S. Angelo, Via Cintia, I-80126 Napoli (Italy); CNR-SPIN, Complesso Universitario di Monte S. Angelo, Via Cintia, I-80126 Napoli (Italy); Wang, X. [CNR-SPIN, Complesso Universitario di Monte S. Angelo, Via Cintia, I-80126 Napoli (Italy); O'Connell, G.; Lunney, J. G. [School of Physics, Trinity College-Dublin, Dublin 2 (Ireland)

    2010-12-01T23:59:59.000Z

    Copper targets are irradiated in the ablation regime by pairs of equal, time-delayed collinear laser pulses separated on a timescale going from {approx_equal}2 ps to {approx_equal}2 ns. The ablation plume is characterized by ion probe diagnostic, fast imaging, and temporally and spatially resolved optical emission spectroscopy. The variation in the ablation efficiency with the delay between the pulses is analyzed by measuring the ablation crater profile with a contact profilometer. The second laser pulse modifies the characteristics of the plasma plume produced by the first pulse and the ablation efficiency. The different mechanisms involved in double pulse ultrafast laser ablation are identified and discussed. The experimental findings are interpreted in the frame of a simple model of the interaction of the second pulse with the nascent ablation plume produced by the first pulse. This model yields consistent and quantitative agreement with the experimental findings predicting the observed experimental trends of the ablation depth reduction and ion yield increase with the delay between the pulses, as well as the characteristic timescale of the observed changes. The possibility of controlling the characteristics of the plumes produced during ultrafast laser ablation via an efficient coupling of the energy of the second pulse to the various ablation components produced by the first pulse is of particular interest in ultrafast pulsed laser deposition and microprobe analyses of materials.

  2. Ultrafast electron cascades in semiconductors driven by intense femtosecond terahertz pulses H. Wen,1 M. Wiczer,3 and A. M. Lindenberg1,2

    E-Print Network [OSTI]

    Ultrafast electron cascades in semiconductors driven by intense femtosecond terahertz pulses H. Wen processing. With wavelengths in the far infrared, near­ half-cycle THz pulses can be thought of as ultrafast,1 M. Wiczer,3 and A. M. Lindenberg1,2 1PULSE Institute, Stanford Linear Accelerator Center, Menlo

  3. Using femtosecond electron pulses as an imaging tool, we can probe ultrafast dynamics by taking snapshots at different time delays. By using femtosecond electron diffraction (FED),

    E-Print Network [OSTI]

    Weston, Ken

    Abstract Using femtosecond electron pulses as an imaging tool, we can probe ultrafast dynamics correlation. Additionally, ultrafast electron shadow imaging (UESI) can explore the dynamics of laser induced System The femtosecond "camera" mentioned above is comprised of an amplified femtosecond pulsed laser

  4. Physics Division: Subatomic Physics Group

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

    Subatomic Physics Physics home Subatomic Physics Site Home About Us Groups Applied Modern Physics, P-21 Neutron Science and Technology, P-23 Plasma Physics, P-24 Subatomic...

  5. Control of molecular rotation in the limit of extreme rotational excitation

    E-Print Network [OSTI]

    Milner, V

    2015-01-01T23:59:59.000Z

    Laser control of molecular rotation is an area of active research. A number of recent studies has aimed at expanding the reach of rotational control to extreme, previously inaccessible rotational states, as well as controlling the directionality of molecular rotation. Dense ensembles of molecules undergoing ultrafast uni-directional rotation, known as molecular superrotors, are anticipated to exhibit unique properties, from spatially anisotropic diffusion and vortex formation to the creation of powerful acoustic waves and tuneable THz radiation. Here we describe our recent progress in controlling molecular rotation in the regime of high rotational excitation. We review two experimental techniques of producing uni-directional rotational wave packets with a "chiral train" of femtosecond pulses and an "optical centrifuge". Three complementary detection methods, enabling the direct observation, characterization and control of the superrotor states, are outlined: the one based on coherent Raman scattering, and two...

  6. Mode-selective vibrational control of charge transport in $?$-conjugated molecular materials

    E-Print Network [OSTI]

    Artem A. Bakulin; Robert Lovrin?i?; Yu Xi; Oleg Selig; Huib J. Bakker; Yves L. A. Rezus; Pabitra K. Nayak; Alexandr Fonari; Veaceslav Coropceanu; Jean-Luc Brédas; David Cahen

    2015-03-02T23:59:59.000Z

    The soft character of organic materials leads to strong coupling between molecular nuclear and electronic dynamics. This coupling opens the way to control charge transport in organic electronic devices by inducing molecular vibrational motions. However, despite encouraging theoretical predictions, experimental realization of such control has remained elusive. Here we demonstrate experimentally that photoconductivity in a model organic optoelectronic device can be controlled by the selective excitation of molecular vibrations. Using an ultrafast infrared laser source to create a coherent superposition of vibrational motions in a pentacene/C60 photoresistor, we observe that excitation of certain modes in the 1500-1700 cm$^{-1}$ region leads to photocurrent enhancement. Excited vibrations affect predominantly trapped carriers. The effect depends on the nature of the vibration and its mode-specific character can be well described by the vibrational modulation of intermolecular electronic couplings. Vibrational control thus presents a new tool for studying electron-phonon coupling and charge dynamics in (bio)molecular materials.

  7. Physics Division annual review, April 1, 1988--March 31, 1989

    SciTech Connect (OSTI)

    Thayer, K.J. (ed.)

    1989-08-01T23:59:59.000Z

    This document discusses the following main topics: Research at Atlas; Operation and Development of Atlas; Medium-Energy Nuclear Physics and Weak Interactions; Theoretical Nuclear Physics; Interactions of Fast Atomic and Molecular Ions with Solid and Gaseous Targets; Atomic Physics at Synchrotron Light Sources; Atomic Physics at Atlas and the ECR Source; Theoretical Atomic Physics; High-Resolution Laser-rf Spectroscopy of Atomic and Molecular Beams; and Fast Ion-Beam/Laser Studies of Atomic and Molecular Structure.

  8. Exploring Ultrafast Chemistry with Long Pulses: Beyond Pump-Probe |

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of Science (SC) Environmental Assessments (EA) /EmailMolecular Solids1

  9. The Behavior of Hydrogen Under Extreme Conditions on Ultrafast Timescales (A "Life at the Frontiers of Energy Research" contest entry from the 2011 Energy Frontier Research Centers (EFRCs) Summit and Forum)

    ScienceCinema (OSTI)

    Mao, Ho-kwang (Director, Center for Energy Frontier Research in Extreme Environments); EFree Staff

    2011-11-02T23:59:59.000Z

    'The Behavior of Hydrogen Under Extreme Conditions on Ultrafast Timescales ' was submitted by the Center for Energy Frontier Research in Extreme Environments (EFree) to the 'Life at the Frontiers of Energy Research' video contest at the 2011 Science for Our Nation's Energy Future: Energy Frontier Research Centers (EFRCs) Summit and Forum. Twenty-six EFRCs created short videos to highlight their mission and their work. EFree is directed by Ho-kwang Mao at the Carnegie Institute of Washington and is a partnership of scientists from thirteen institutions.The Office of Basic Energy Sciences in the U.S. Department of Energy's Office of Science established the 46 Energy Frontier Research Centers (EFRCs) in 2009. These collaboratively-organized centers conduct fundamental research focused on 'grand challenges' and use-inspired 'basic research needs' recently identified in major strategic planning efforts by the scientific community. The overall purpose is to accelerate scientific progress toward meeting the nation's critical energy challenges. The mission of Energy Frontier Research in Extreme Environments is 'to accelerate the discovery and creation of energy-relevant materials using extreme pressures and temperatures.' Research topics are: catalysis (CO{sub 2}, water), photocatalysis, solid state lighting, optics, thermelectric, phonons, thermal conductivity, solar electrodes, fuel cells, superconductivity, extreme environment, radiation effects, defects, spin dynamics, CO{sub 2} (capture, convert, store), greenhouse gas, hydrogen (fuel, storage), ultrafast physics, novel materials synthesis, and defect tolerant materials.

  10. Comparison of 13CO Line and Far-Infrared Continuum Emission as a Diagnostic of Dust and Molecular Gas Physical Conditions: II. The Simulations: Testing the Method

    E-Print Network [OSTI]

    W. F. Wall

    2006-01-24T23:59:59.000Z

    The reliability of modeling the far-IR continuum to 13CO J=1-0 spectral line ratios applied to the Orion clouds (Wall 2006) is tested by applying the models to simulated data. The two-component models are found to give the dust-gas temperature difference, $\\DT$, to within 1 or 2$ $K. However, other parameters like the column density per velocity interval and the gas density can be wrong by an order of magnitude or more. In particular, the density can be systematically underestimated by an order of magnitude or more. The overall mass of the clouds is estimated correctly to within a few percent. The one-component models estimate the column density per velocity interval and density within factors of 2 or 3, but their estimates of $\\DT$ can be wrong by 20$ $K. They also underestimate the mass of the clouds by 40-50%. These results may permit us to reliably constrain estimates of the Orion clouds' physical parameters, based on the real observations of the far-IR continuum and 13CO J=1-0 spectral line. Nevertheless, other systematics must be treated first. These include the effects of background/foreground subtraction, effects of the HI component of the ISM, and others. These will be discussed in a future paper (Wall 2006a).

  11. Ultra--fast carriers relaxation in bulk silicon following photo--excitation with a short and polarized laser pulse

    E-Print Network [OSTI]

    Sangalli, Davide

    2014-01-01T23:59:59.000Z

    A novel approach based on the merging of the out--of--equilibrium Green's function method with the ab-initio, Density--Functional--Theory is used to describe the ultra--fast carriers relaxation in Silicon. The results are compared with recent two photon photo--emission measurements. We show that the interpretation of the carrier relaxation in terms of L -> X inter--valley scattering is not correct. The ultra--fast dynamics measured experimentally is, instead, due to the scattering between degenerate $L$ states that is activated by the non symmetric population of the conduction bands induced by the laser field. This ultra--fast relaxation is, then, entirely due to the specific experimental setup and it can be interpreted by introducing a novel definition of the quasi--particle lifetimes in an out--of--equilibrium context.

  12. Processing and thermal properties of molecularly oriented polymers

    E-Print Network [OSTI]

    Skow, Erik (Erik Dean)

    2007-01-01T23:59:59.000Z

    High molecular weight polymers that are linear in molecular construction can be oriented such that some of their physical properties in the oriented direction are enhanced. For over 50 years polymer orientation and processing ...

  13. Ultra-fast outflows (aka UFOs) from AGNs and QSOs

    E-Print Network [OSTI]

    Cappi, M; Giustini, M

    2013-01-01T23:59:59.000Z

    During the last decade, strong observational evidence has been accumulated for the existence of massive, high velocity winds/outflows (aka Ultra Fast Outflows, UFOs) in nearby AGNs and in more distant quasars. Here we briefly review some of the most recent developments in this field and discuss the relevance of UFOs for both understanding the physics of accretion disk winds in AGNs, and for quantifying the global amount of AGN feedback on the surrounding medium.

  14. Ultrafast laser based coherent control methods for explosives detection

    SciTech Connect (OSTI)

    Moore, David Steven [Los Alamos National Laboratory

    2010-12-06T23:59:59.000Z

    The detection of explosives is a notoriously difficult problem, especially at stand-off, due to their (generally) low vapor pressure, environmental and matrix interferences, and packaging. We are exploring Optimal Dynamic Detection of Explosives (ODD-Ex), which exploits the best capabilities of recent advances in laser technology and recent discoveries in optimal shaping of laser pulses for control of molecular processes to significantly enhance the standoff detection of explosives. The core of the ODD-Ex technique is the introduction of optimally shaped laser pulses to simultaneously enhance sensitivity to explosives signatures while dramatically improving specificity, particularly against matrix materials and background interferences. These goals are being addressed by operating in an optimal non-linear fashion, typically with a single shaped laser pulse inherently containing within it coherently locked control and probe subpulses. Recent results will be presented.

  15. A compact streak camera for 150 fs time resolved measurement of bright pulses in ultrafast electron diffraction

    SciTech Connect (OSTI)

    Kassier, G. H.; Haupt, K.; Erasmus, N.; Rohwer, E. G.; Bergmann, H. M. von; Schwoerer, H. [Laser Research Institute, University of Stellenbosch, Private Bag X1, 7602 Matieland (South Africa); Coelho, S. M. M.; Auret, F. D. [Department of Physics, University of Pretoria, Pretoria 0002 (South Africa)

    2010-10-15T23:59:59.000Z

    We have developed a compact streak camera suitable for measuring the duration of highly charged subrelativistic femtosecond electron bunches with an energy bandwidth in the order of 0.1%, as frequently used in ultrafast electron diffraction (UED) experiments for the investigation of ultrafast structural dynamics. The device operates in accumulation mode with 50 fs shot-to-shot timing jitter, and at a 30 keV electron energy, the full width at half maximum temporal resolution is 150 fs. Measured durations of pulses from our UED gun agree well with the predictions from the detailed charged particle trajectory simulations.

  16. Charge exchange molecular ion source

    DOE Patents [OSTI]

    Vella, Michael C.

    2003-06-03T23:59:59.000Z

    Ions, particularly molecular ions with multiple dopant nucleons per ion, are produced by charge exchange. An ion source contains a minimum of two regions separated by a physical barrier and utilizes charge exchange to enhance production of a desired ion species. The essential elements are a plasma chamber for production of ions of a first species, a physical separator, and a charge transfer chamber where ions of the first species from the plasma chamber undergo charge exchange or transfer with the reactant atom or molecules to produce ions of a second species. Molecular ions may be produced which are useful for ion implantation.

  17. Ultrafast imaging interferometry at femtosecond-laser-excited surfaces

    SciTech Connect (OSTI)

    Temnov, Vasily V.; Sokolowski-Tinten, Klaus; Zhou Ping; Linde, Dietrich von der [Experimentelle Physik IIb, Universitaet Dortmund, 44221 Dortmund (Germany); Institut fuer Experimentelle Physik, Universitaet Duisburg-Essen, 45117 Essen (Germany)

    2006-09-15T23:59:59.000Z

    A simple and robust setup for femtosecond time-resolved imaging interferometry of surfaces is described. The apparatus is capable of measuring both very small phase shifts ({approx}3x10{sup -2} rad) and amplitude changes ({approx}1%) with micrometer spatial resolution ({approx}1 {mu}m). Interferograms are processed using a 2D-Fourier transform algorithm. We discuss the image formation and the physical interpretation of the measured interferograms. The technique is applied to measure transient changes of a GaAs surface irradiated with intense femtosecond laser pulses with fluences near the ablation threshold.

  18. Ultrafast studies of organometallic photochemistry: The mechanism of carbon-hydrogen bond activation in solution

    SciTech Connect (OSTI)

    Bromberg, S.E.

    1998-05-01T23:59:59.000Z

    When certain organometallic compounds are photoexcited in room temperature alkane solution, they are able to break or activate the C-H bonds of the solvent. Understanding this potentially practical reaction requires a detailed knowledge of the entire reaction mechanism. Because of the dynamic nature of chemical reactions, time-resolved spectroscopy is commonly employed to follow the important events that take place as reactants are converted to products. For the organometallic reactions examined here, the electronic/structural characteristics of the chemical systems along with the time scales for the key steps in the reaction make ultrafast UV/Vis and IR spectroscopy along with nanosecond Step-Scan FTIR spectroscopy the ideal techniques to use for this study. An initial study of the photophysics of (non-activating) model metal carbonyls centering on the photodissociation of M(CO){sub 6} (M = Cr, W, Mo) was carried out in alkane solutions using ultrafast IR spectroscopy. Next, picosecond UV/vis studies of the C-H bond activation reaction of Cp{sup *}M(CO){sub 2} (M = Rh, Ir), conducted in room temperature alkane solution, are described in an effort to investigate the origin of the low quantum yield for bond cleavage ({approximately}1%). To monitor the chemistry that takes place in the reaction after CO is lost, a system with higher quantum yield is required. The reaction of Tp{sup *}Rh(CO){sub 2} (Tp{sup *} = HB-Pz{sub 3}{sup *}, Pz{sup *} = 3,5-dimethylpyrazolyl) in alkanes has a quantum yield of {approximately}30%, making time resolved spectroscopic measurements possible. From ultrafast IR experiments, two subsequently formed intermediates were observed. The nature of these intermediates are discussed and the first comprehensive reaction mechanism for a photochemical C-H activating organometallic complex is presented.

  19. List of Examiners for MVMod MASTER of Science in Physics

    E-Print Network [OSTI]

    Heermann, Dieter W.

    List of Examiners for MVMod MASTER of Science in Physics Astronomy and Astrophysics: Bartelmann, Quirrenbach, Rix, Schaefer, Springel, Spurzem, Wagner, Wambsganß Atomic, Molecular and Optical Physics: Blaum, Schlichting, Schwarz, Spatz, Tanaka Condensed Matter Physics: Enss, Klingeler, Kowalsky, Pucci, Winnacker

  20. Physics Division annual review, April 1, 1991--March 31, 1992

    SciTech Connect (OSTI)

    Henning, W.F.

    1992-08-01T23:59:59.000Z

    This report contains brief discusses on topics in the following areas: Research at atlas; operation and development of atlas; medium-energy nuclear physics and weak interactions; theoretical nuclear physics; and atomic and molecular physics research.

  1. Double-Wall Carbon Nanotubes for Wide-Band, Ultrafast Pulse Generation

    E-Print Network [OSTI]

    Hasan, Tawfique; Sun, Zhipei; Tan, PingHeng; Popa, Daniel; Flahaut, Emmanuel; Kelleher, Edmund J. R.; Bonaccorso, Francesco; Wang, Fengqiu; Jiang, Zhe; Torrisi, Felice; Privitera, Giulia; Nicolosi, Valeria; Ferrari, Andrea C.

    2014-04-15T23:59:59.000Z

    , respectively). 48 Thus, in terms of carrier dynamics, DWNTs are comparable to SWNTs. Further, DWNTs can have outer and inner wall combinations with different electronic types (semi- conducting, s, or metallic, m) in their structures (outer-inner: s-s, s-m, m... .; Hennrich, F.; White, I. H.; Milne, W. I.; Ferrari, A. C. Carbon Nanotube-Polycarbonate Composites for Ultrafast La- sers. Adv. Mater. 2008, 20, 4040–4043. 21. Wang, F.; Rozhin, A. G.; Scardaci, V.; Sun, Z.; Hennrich, F.; White, I. H.; Milne, W. I.; Ferrari...

  2. Ultrafast magneto-photocurrents in GaAs: Separation of surface and bulk contributions

    E-Print Network [OSTI]

    Schmidt, Christian B; Tarasenko, Sergey A; Bieler, Mark

    2015-01-01T23:59:59.000Z

    We induce ultrafast magneto-photocurrents in a GaAs crystal employing interband excitation with femtosecond laser pulses at room temperature and non-invasively separate surface and bulk contributions to the overall current response. The separation between the different symmetry contributions is achieved by measuring the simultaneously emitted terahertz radiation for different sample orientations. Excitation intensity and photon energy dependences of the magneto-photocurrents for linearly and circularly polarized excitations reveal an involvement of different microscopic origins, one of which we believe is the inverse Spin-Hall effect. Our experiments are important for a better understanding of the complex momentum-space carrier dynamics in magnetic fields.

  3. Electron Pulse Compression with a Practical Reflectron Design for Ultrafast Electron Diffraction

    E-Print Network [OSTI]

    Wang, Yihua

    2013-01-01T23:59:59.000Z

    Ultrafast electron diffraction (UED) is a powerful method for studying time-resolved structural changes. Currently, space charge induced temporal broadening prevents obtaining high brightness electron pulses with sub-100 fs durations limiting the range of phenomena that can be studied with this technique. We review the state of the the art of UED in this respect and propose a practical design for reflectron based pulse compression which utilizes only electro-static optics and has a tunable temporal focal point. Our simulation shows that this scheme is capable of compressing an electron pulse containing 100,000 electrons with 60:1 temporal compression ratio.

  4. Pump-probe imaging of laser-induced periodic surface structures after ultrafast irradiation of Si

    SciTech Connect (OSTI)

    Murphy, Ryan D. [Applied Physics Program, University of Michigan, Ann Arbor, Michigan 48109 (United States)] [Applied Physics Program, University of Michigan, Ann Arbor, Michigan 48109 (United States); Torralva, Ben [Department of Atmospheric, Oceanic and Space Sciences, University of Michigan, Ann Arbor, Michigan 48109 (United States)] [Department of Atmospheric, Oceanic and Space Sciences, University of Michigan, Ann Arbor, Michigan 48109 (United States); Adams, David P. [Sandia National Laboratories, Albuquerque, New Mexico 87123 (United States)] [Sandia National Laboratories, Albuquerque, New Mexico 87123 (United States); Yalisove, Steven M. [Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109 (United States)] [Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109 (United States)

    2013-09-30T23:59:59.000Z

    Ultrafast pump-probe microscopy has been used to investigate laser-induced periodic surface structure (LIPSS) formation on polished Si surfaces. A crater forms on the surface after irradiation by a 150 fs laser pulse, and a second, subsequent pulse forms LIPSS within the crater. Sequentially delayed images show that LIPSS with a periodicity slightly less than the fundamental laser wavelength of 780 nm appear on Si surfaces ?50 ps after arrival of the second pump laser pulse, well after the onset of melting. LIPSS are observed on the same timescale as material removal, suggesting that their formation involves material ejection.

  5. Broadband electromagnetic response and ultrafast dynamics of few-layer epitaxial graphene

    SciTech Connect (OSTI)

    Choi, Hyunyong; Borondics, Ferenc; Siegel, David A.; Zhou, Shuyun Y.; Martin, Michael C.; Lanzara, Alessandra; Kaindl, Robert A.

    2009-03-26T23:59:59.000Z

    We study the broadband optical conductivity and ultrafast carrier dynamics of epitaxial graphene in the few-layer limit. Equilibrium spectra of nominally buffer, monolayer, and multilayer graphene exhibit significant terahertz and near-infrared absorption, consistent with a model of intra- and interband transitions in a dense Dirac electron plasma. Non-equilibrium terahertz transmission changes after photoexcitation are shown to be dominated by excess hole carriers, with a 1.2-ps mono-exponential decay that refects the minority-carrier recombination time.

  6. Single Photon Subradiance:Quantum control of spontaneous emission and ultrafast readout

    E-Print Network [OSTI]

    Marlan O. Scully

    2015-05-12T23:59:59.000Z

    Recent work has shown that collective single photon emission from an ensemble of resonate two-level atoms is a rich field of study. For example single photon superradiance from an extended ensemble yields enhanced directional spontaneous emission; and when the effects of the collective Lamb shift are included it becomes even more interesting. The present paper addresses the flip side of superradiance, i.e., subradiance. Single photon subradiant states are potentially stable against collective spontaneous emission and can have ultrafast readout. In particular, it is shown how many atom collective effects can be used to control emission by preparing and switching between subradiant and superradiant states.

  7. Differential ultrafast all-optical switching of the resonances of a micropillar cavity

    SciTech Connect (OSTI)

    Thyrrestrup, Henri, E-mail: h.t.nielsen@utwente.nl; Yüce, Emre; Ctistis, Georgios; Vos, Willem L. [Complex Photonic Systems (COPS), MESA Institute for Nanotechnology, University of Twente, 7500 AE Enschede (Netherlands); Claudon, Julien; Gérard, Jean-Michel, E-mail: jean-michel.gerard@cea.fr [University Grenoble Alpes, INAC-SP2M, Nanophysics and Semiconductors Lab, F-38000 Grenoble (France); CEA, INAC-SP2M, Nanophysics and Semiconductors Lab, F-38000 Grenoble (France)

    2014-09-15T23:59:59.000Z

    We perform frequency- and time-resolved all-optical switching of a GaAs-AlAs micropillar cavity using an ultrafast pump-probe setup. The switching is achieved by two-photon excitation of free carriers. We track the cavity resonances in time with a high frequency resolution. The pillar modes exhibit simultaneous frequency shifts, albeit with markedly different maximum switching amplitudes and relaxation dynamics. These differences stem from the non-uniformity of the free carrier density in the micropillar, and are well understood by taking into account the spatial distribution of injected free carriers, their spatial diffusion and surface recombination at micropillar sidewalls.

  8. Ultrafast Materials and Chemical Sciences FOA | U.S. DOE Office of Science

    Office of Science (SC) Website

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What'sis Taking Over OurTheBrookhaven NationalRegionals » High School(SC) The(SC) Ultrafast

  9. alkane molecular ions: Topics by E-print Network

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

    1977-01-01 25 Blackbody thermometry with cold molecular ions and application to ion-based frequency standards Physics Websites Summary: Blackbody thermometry with cold...

  10. atomistic molecular simulation: Topics by E-print Network

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

    22 23 24 25 Next Page Last Page Topic Index 1 Simulational nanoengineering: Molecular dynamics implementation of an atomistic Stirling engine Physics Websites Summary: Simulational...

  11. From gyroscopic to thermal motion: a crossover in the dynamics of molecular superrotors

    E-Print Network [OSTI]

    Milner, A A; Rezaiezadeh, K; Milner, V

    2015-01-01T23:59:59.000Z

    Localized heating of a gas by intense laser pulses leads to interesting acoustic, hydrodynamic and optical effects with numerous applications in science and technology, including controlled wave guiding and remote atmosphere sensing. Rotational excitation of molecules can serve as the energy source for raising the gas temperature. Here, we study the dynamics of energy transfer from the molecular rotation to heat. By optically imaging a cloud of molecular superrotors, created with an optical centrifuge, we experimentally identify two separate and qualitatively different stages of its evolution. The first non-equilibrium "gyroscopic" stage is characterized by the modified optical properties of the centrifuged gas - its refractive index and optical birefringence, owing to the ultrafast directional molecular rotation, which survives tens of collisions. The loss of rotational directionality is found to overlap with the release of rotational energy to heat, which triggers the second stage of thermal expansion. The ...

  12. Ultrafast UV Pump/IR Probe Studies of C-H Activation in Linear, Cyclic, and Aryl Hydrocarbons

    E-Print Network [OSTI]

    Harris, Charles B.

    Ultrafast UV Pump/IR Probe Studies of C-H Activation in Linear, Cyclic, and Aryl Hydrocarbons, cyclic, and aromatic hydrocarbon solvents on a femtosecond to microsecond time scale. These results have revealed that the structure of the hydrocarbon substrate affects the final C-H bond activation step, which

  13. Ultrafast Laser Pulse Control of Exciton Dynamics: A Computational Study on the FMO Ben Bru1ggemann and Volkhard May*

    E-Print Network [OSTI]

    Röder, Beate

    Ultrafast Laser Pulse Control of Exciton Dynamics: A Computational Study on the FMO Complex Ben Bru, D-12489 Berlin, Germany ReceiVed: February 4, 2004; In Final Form: May 23, 2004 Femtosecond laser-pulse on the Frenkel exciton model for the bacteriochlorophyll (BChl) Qy-excitations, the laser- pulse-driven exciton

  14. REVIEW OF SCIENTIFIC INSTRUMENTS 84, 123906 (2013) A table-top, repetitive pulsed magnet for nonlinear and ultrafast

    E-Print Network [OSTI]

    Kono, Junichiro

    2013-01-01T23:59:59.000Z

    REVIEW OF SCIENTIFIC INSTRUMENTS 84, 123906 (2013) A table-top, repetitive pulsed magnet for nonlinear and ultrafast spectroscopy in high magnetic fields up to 30 T G. Timothy Noe II,1 Hiroyuki Nojiri and Computer Engineering, Rice University, Houston, Texas 77005, USA 2 Institute for Materials Research, Tohoku

  15. Hydrogen Bond Switching among Flavin and Amino Acid Side Chains in the BLUF Photoreceptor Observed by Ultrafast Infrared Spectroscopy

    E-Print Network [OSTI]

    van Stokkum, Ivo

    Hydrogen Bond Switching among Flavin and Amino Acid Side Chains in the BLUF Photoreceptor Observed hydrogen-bond network with nearby amino acid side chains, including a highly conserved tyrosine and glutamine. The participation of particular amino acid side chains in the ultrafast hydrogen-bond switching

  16. Controlling Graphene Ultrafast Hot Carrier Response from Metal-like to Semiconductor-like by Electrostatic Gating

    E-Print Network [OSTI]

    Zettl, Alex

    with dry nitrogen during the measurement. Sample preparation We grow single layer graphene on copper foil1 Controlling Graphene Ultrafast Hot Carrier Response from Metal-like to Semiconductor electro-optic sampling.2 The focused THz beam at our graphene sample has a diameter of 1 mm. For optical

  17. Ultrafast Microfluidic Mixer and Freeze-Quenching Yu Lin, Gary J. Gerfen, Denis L. Rousseau, and Syun-Ru Yeh*

    E-Print Network [OSTI]

    Yeh, Syun-Ru

    Ultrafast Microfluidic Mixer and Freeze-Quenching Device Yu Lin, Gary J. Gerfen, Denis L. Rousseau fluids. To overcome these problems, we have designed and tested a novel microfluidic silicon mixer. The mixed-solution jet, with a cross section of 10 µm × 100 µm, exits from the microfluidic silicon mixer

  18. IEEE Trans Ultrason Ferroelectr Freq Control . Author manuscript Combined passive detection and ultrafast active imaging of cavitation

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Gateaué ô Abstract The activation of natural gas nuclei to induce larger and ultrafast active imaging over a large volume and with the same multi-element probe. Bubble nucleation ; ultrasonography ; Phantoms, Imaging ; Sheep ; Signal Processing, Computer-Assisted ; Transducers ; Ultrasonography

  19. H.sub.2O doped WO.sub.3, ultra-fast, high-sensitivity hydrogen sensors

    DOE Patents [OSTI]

    Liu, Ping (Denver, CO); Tracy, C. Edwin (Golden, CO); Pitts, J. Roland (Lakewood, CO); Lee, Se-Hee (Lakewood, CO)

    2011-03-22T23:59:59.000Z

    An ultra-fast response, high sensitivity structure for optical detection of low concentrations of hydrogen gas, comprising: a substrate; a water-doped WO.sub.3 layer coated on the substrate; and a palladium layer coated on the water-doped WO.sub.3 layer.

  20. Free electron properties of metals under ultrafast laser-induced electron-phonon nonequilibrium: a first-principles study

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Free electron properties of metals under ultrafast laser-induced electron-phonon nonequilibrium modelled based on the free electron classical theory, the free electron number is a key parameter. However or delocalized electronic states, temperature dependent free electron numbers are evaluated for a series

  1. Nonlinear Ultrafast Spectroscopy of Electron and Energy Transfer in Molecule Complexes

    SciTech Connect (OSTI)

    Mukamel, Shaul

    2006-02-09T23:59:59.000Z

    The proposed research program will focus on the development of a unified dynamical theoretical framework for calculating the optical response of molecular assemblies and applying it towards studying the interplay of energy and charge transfer in artificial chromophore-aggregate complexes. Applications will be made to poly (p phenylene vinylene), (PPV) oligomers, several families of stilbenoid aggregates with stacking through a cyclophane group, coupled porphyrin arrays, and energy funneling in phenylacetylene dendrimers. The approach is based on formulating the problem using the density- matrix and developing Liouville-space techniques which provide physical insight and are particularly suitable for computing both coherent and incoherent transport. A physical picture based on collective electronic normal modes which represent the dynamics of the optically-driven reduced single electron density matrix will be established. Femtosecond signals and optical properties will be directly related to the motions of electron-hole pairs in real space, completely avoiding the calculation of many-electron excited-state wavefunctions, thus, considerably reducing computational effort. Vibrational and solvent effects will be incorporated. Guidelines for the synthesis of new donor/bridge/acceptor molecules with desired properties such as carrier transport, optical response time scales and fluorescence quantum yields will be developed. The analogy with Thz emission spectroscopy which probes charge carrier dynamic is in semiconductor superlattices will be explored. A systematic procedure for identifying the electronic coherence sizes which control the transport and optical properties will be developed. Localization of electronic transition density matrices of large molecules will be used to break the description of their optical response into coupled chromophores. The proposal is divided into four parts: (i) Collective-Oscillator Representation of Electronic Excitations in Molecular Assemblies; (ii) Nonlinear Optical Spectroscopy of Coupled Chromophores; (iii) Long-Range Electron Transfer and Transport in Solvents with Complex Spectral Densities; (iv) Probing Exciton-Migration by Coherent Femtosecond Spectroscopies.

  2. Emission dynamics of an expanding ultrafast-laser produced Zn plasma under different ambient pressures

    SciTech Connect (OSTI)

    Smijesh, N.; Philip, Reji [Raman Research Institute, C.V. Raman Avenue, Sadashivanagar, Bangalore 560080 (India)] [Raman Research Institute, C.V. Raman Avenue, Sadashivanagar, Bangalore 560080 (India)

    2013-09-07T23:59:59.000Z

    We report time and space resolved spectral measurements of neutral Zn emission from an ultrafast laser produced plasma, generated by the irradiation of a Zn target with laser pulses of 100 femtoseconds duration, carried out in a broad ambient pressure range of 0.05 to 100 Torr. The measurement is done for three different axial positions in the expanding plume. The spectra are rich in neutral Zn (Zn I) emissions at 334.5 nm, 468 nm, 472 nm, 481 nm, and 636 nm, respectively, depicting the characteristic triplet structure of Zn. Fast as well as slow peaks are observed in the time of flight data of 481 nm emission, which arise from recombination and atomic contributions, respectively, occurring at different time scales. Average speeds of the fast atomic species do not change appreciably with ambient pressure. The plasma parameters (electron temperature and number density) are evaluated from the measured optical emission spectra. The rates of ionization and recombination can be enhanced by a double-pulse excitation configuration in which optical energy is coupled to the ultrafast plasma through a delayed laser pulse.

  3. CITIUS: An infrared-extreme ultraviolet light source for fundamental and applied ultrafast science

    SciTech Connect (OSTI)

    Grazioli, C.; Gauthier, D.; Ivanov, R.; De Ninno, G. [Laboratory of Quantum Optics, University of Nova Gorica, Nova Gorica (Slovenia) [Laboratory of Quantum Optics, University of Nova Gorica, Nova Gorica (Slovenia); Elettra Sincrotrone Trieste, Trieste (Italy)] [Italy; Callegari, C.; Spezzani, C. [Elettra Sincrotrone Trieste, Trieste (Italy)] [Elettra Sincrotrone Trieste, Trieste (Italy); Ciavardini, A. [Sapienza University, Rome (Italy)] [Sapienza University, Rome (Italy); Coreno, M. [Elettra Sincrotrone Trieste, Trieste (Italy) [Elettra Sincrotrone Trieste, Trieste (Italy); Institute of Inorganic Methodologies and Plasmas (CNR-IMIP), Montelibretti, Roma (Italy); Frassetto, F.; Miotti, P.; Poletto, L. [Institute of Photonics and Nanotechnologies (CNR-IFN), Padova (Italy)] [Institute of Photonics and Nanotechnologies (CNR-IFN), Padova (Italy); Golob, D. [Kontrolni Sistemi d.o.o., Sežana (Slovenia)] [Kontrolni Sistemi d.o.o., Sežana (Slovenia); Kivimäki, A. [Institute of Materials Manufacturing (CNR-IOM), TASC Laboratory, Trieste (Italy)] [Institute of Materials Manufacturing (CNR-IOM), TASC Laboratory, Trieste (Italy); Mahieu, B. [Elettra Sincrotrone Trieste, Trieste (Italy) [Elettra Sincrotrone Trieste, Trieste (Italy); Service des Photons Atomes et Molécules, Commissariat à l'Energie Atomique, Centre d'Etudes de Saclay, Bâtiment 522, 91191 Gif-sur-Yvette (France); Bu?ar, B.; Merhar, M. [Laboratory of Mechanical Processing Technologies, University of Ljubljana, Ljubljana (Slovenia)] [Laboratory of Mechanical Processing Technologies, University of Ljubljana, Ljubljana (Slovenia); Polo, E. [Institute of Organic Synthesis and Photoreactivity (CNR-ISOF), Ferrara (Italy)] [Institute of Organic Synthesis and Photoreactivity (CNR-ISOF), Ferrara (Italy); Ressel, B. [Laboratory of Quantum Optics, University of Nova Gorica, Nova Gorica (Slovenia)] [Laboratory of Quantum Optics, University of Nova Gorica, Nova Gorica (Slovenia)

    2014-02-15T23:59:59.000Z

    We present the main features of CITIUS, a new light source for ultrafast science, generating tunable, intense, femtosecond pulses in the spectral range from infrared to extreme ultraviolet (XUV). The XUV pulses (about 10{sup 5}-10{sup 8} photons/pulse in the range 14-80 eV) are produced by laser-induced high-order harmonic generation in gas. This radiation is monochromatized by a time-preserving monochromator, also allowing one to work with high-resolution bandwidth selection. The tunable IR-UV pulses (10{sup 12}-10{sup 15} photons/pulse in the range 0.4-5.6 eV) are generated by an optical parametric amplifier, which is driven by a fraction of the same laser pulse that generates high order harmonics. The IR-UV and XUV pulses follow different optical paths and are eventually recombined on the sample for pump-probe experiments. We also present the results of two pump-probe experiments: with the first one, we fully characterized the temporal duration of harmonic pulses in the time-preserving configuration; with the second one, we demonstrated the possibility of using CITIUS for selective investigation of the ultra-fast dynamics of different elements in a magnetic compound.

  4. DEPARTMENT OF PHYSICS Physics 20300

    E-Print Network [OSTI]

    Lombardi, John R.

    DEPARTMENT OF PHYSICS Syllabus Physics 20300 General Physics Designation: Required Undergraduate Catalog description: For majors in the life sciences (biology, medicine, dentistry, psychology, physical therapy) and for liberal arts students. Fundamental ideas and laws of physics from mechanics to modern

  5. DEPARTMENT OF PHYSICS Physics 32100

    E-Print Network [OSTI]

    Lombardi, John R.

    DEPARTMENT OF PHYSICS Syllabus Physics 32100 Modern Physics for Engineers Designation to one- electron atoms, atomic shell structure and periodic table; nuclear physics, relativity. Prerequisites: Prereq.: Physics 20800 or equivalent, Math 20300 or 20900 (elective for Engineering students

  6. Ultrafast Fluorescence Relaxation Spectroscopy of 6,7-Dimethyl-(8-ribityl)-lumazine and Riboflavin, Free and Bound to Antenna Proteins from Bioluminescent Bacteria

    E-Print Network [OSTI]

    van Stokkum, Ivo

    Ultrafast Fluorescence Relaxation Spectroscopy of 6,7-Dimethyl-(8-ribityl)-lumazine and Riboflavin-(8-ribityl)-lumazine (lumazine) and riboflavin in an aqueous buffer and both ligands when

  7. Effective Analysis of NGS Metagenomic Data with Ultra-Fast Clustering Algorithms (MICW - Metagenomics Informatics Challenges Workshop: 10K Genomes at a Time)

    ScienceCinema (OSTI)

    Li, Weizhong [San Diego Supercomputer Center

    2013-01-22T23:59:59.000Z

    San Diego Supercomputer Center's Weizhong Li on "Effective Analysis of NGS Metagenomic Data with Ultra-fast Clustering Algorithms" at the Metagenomics Informatics Challenges Workshop held at the DOE JGI on October 12-13, 2011.

  8. Molecular Physics 2012, 110, iFirst

    E-Print Network [OSTI]

    Maier, John Paul

    the optical cavity. A numerical example is given for atomic lines of neon and the measurements carried out the first-order differential equation driving the radiation decay rate inside the cavity, coupled

  9. Molecular Gas in Quasar Hosts

    E-Print Network [OSTI]

    Richard Barvainis

    1997-01-29T23:59:59.000Z

    The study of molecular gas in quasar host galaxies addresses a number of interesting questions pertaining to the hosts' ISM, to unified schemes relating quasars and IR galaxies, and to the processes fueling nuclear activity. In this contribution I review observations of molecular gas in quasar hosts from z=0.06 to z=4.7. The Cloverleaf quasar at z=2.5 is featured as a case where there are now enough detected transitions (four in CO, and one each in CI and HCN) to allow detailed modeling of physical conditions in the molecular ISM. We find that the CO-emitting gas is warmer, denser, and less optically thick than that found in typical Galactic molecular clouds. These differences are probably due to the presence of the luminous quasar in the nucleus of the Cloverleaf's host galaxy.

  10. Sandia Energy - Molecular Geochemistry

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

    molecular spectroscopy, and molecular simulation to complex multicomponent and multiphase systems; particular emphasis on the use of molecular simulation and various...

  11. Frontiers for Discovery in High Energy Density Physics

    SciTech Connect (OSTI)

    Davidson, R. C.; Katsouleas, T.; Arons, J.; Baring, M.; Deeney, C.; Di Mauro, L.; Ditmire, T.; Falcone, R.; Hammer, D.; Hill, W.; Jacak, B.; Joshi, C.; Lamb, F.; Lee, R.; Logan, B. G.; Melissinos, A.; Meyerhofer, D.; Mori, W.; Murnane, M.; Remington, B.; Rosner, R.; Schneider, D.; Silvera, I.; Stone, J.; Wilde, B.; Zajc. W.

    2004-07-20T23:59:59.000Z

    The report is intended to identify the compelling research opportunities of high intellectual value in high energy density physics. The opportunities for discovery include the broad scope of this highly interdisciplinary field that spans a wide range of physics areas including plasma physics, laser and particle beam physics, nuclear physics, astrophysics, atomic and molecular physics, materials science and condensed matter physics, intense radiation-matter interaction physics, fluid dynamics, and magnetohydrodynamics

  12. Ultrafast Control of Magnetism in Ferromagnetic Semiconductors via Photoexcited Transient Carriers

    SciTech Connect (OSTI)

    Cotoros, Ingrid A.

    2008-12-12T23:59:59.000Z

    The field of spintronics offers perspectives for seamless integration of coupled and inter-tunable electrical and magnetic properties in a single device. For integration of the spin degree of freedom with current electronic technology, new semiconductors are needed that show electrically-tunable magnetic properties at room temperature and above. Dilute magnetic semiconductors derived from III-V compounds, like GaMnAs and InMnAs, show coupled and tunable magnetic, transport, and optical properties, due to the fact that their ferromagnetism is hole-mediated. These unconventional materials are ideal systems for manipulating the magnetic order by changing the carrier polarization, population density, and energy band distribution of the complementary subsystem of holes. This is the main theme we cover in this thesis. In particular, we develop a unique setup by use of ultraviolet pump, near-infrared probe femtosecond laser pulses, that allows for magneto-optical Kerr effect (MOKE) spectroscopy experiments. We photo-excite transient carriers in our samples, and measure the induced transient magnetization dynamics. One set of experiments performed allowed us to observe for the first time enhancement of the ferromagnetic order in GaMnAs, on an ultrafast time scale of hundreds of picoseconds. The corresponding transient increase of Curie temperature (Tc, the temperature above which a ferromagnetic material loses its permanent magnetism) of about 1 K for our experimental conditions is a very promising result for potential spintronics applications, especially since it is seconded by observation of an ultrafast ferromagnetic to paramagnetic phase transition above Tc. In a different set of experiments, we"write" the magnetization in a particular orientation in the sample plane. Using an ultrafast scheme, we alter the distribution of holes in the system and detect signatures of the particular memory state in the subsequent magnetization dynamics, with unprecedented hundreds of femtosecond detection speed. The femtosecond cooperative magnetic phenomena presented here further our understanding of Mn-hole correlations in III-V dilute magnetic semiconductors, and may well represent universal principles of a large class of carrier-mediated ferromagnetic materials. Thus they offer perspectives for future terahertz (1012 Hz) speed"spintronic" functional devices.

  13. Evidence for ultra-fast heating in intense-laser irradiated reduced-mass targets

    SciTech Connect (OSTI)

    Neumayer, P.; Gumberidze, A.; Hochhaus, D. C. [ExtreMe Matter Institute EMMI and Research Division, GSI Helmholtzzentrum fuer Schwerionenforschung, 64291 Darmstadt (Germany); Frankfurt Institute for Advanced Studies FIAS, 60438 Frankfurt am Main (Germany); Aurand, B.; Stoehlker, T. [Helmholtzzentrum fuer Schwerionenforschung GSI, 64291 Darmstadt (Germany); Helmholtz Institute Jena, 07743 Jena (Germany); Costa Fraga, R. A.; Kalinin, A. [Institut fuer Kernphysik, J. W. Goethe University Frankfurt, 60438 Frankfurt am Main (Germany); Ecker, B. [Johannes Gutenberg University Mainz, 55099 Mainz (Germany); Helmholtz Institute Jena, 07743 Jena (Germany); Grisenti, R. E. [Institut fuer Kernphysik, J. W. Goethe University Frankfurt, 60438 Frankfurt am Main (Germany); Helmholtzzentrum fuer Schwerionenforschung GSI, 64291 Darmstadt (Germany); Kaluza, M. C. [Helmholtz Institute Jena, 07743 Jena (Germany); IOQ Institute of Optics and Quantum Electronics, University of Jena (Germany); Kuehl, T. [Johannes Gutenberg University Mainz, 55099 Mainz (Germany); Helmholtzzentrum fuer Schwerionenforschung GSI, 64291 Darmstadt (Germany); Helmholtz Institute Jena, 07743 Jena (Germany); Polz, J. [IOQ Institute of Optics and Quantum Electronics, University of Jena (Germany); Reuschl, R. [ExtreMe Matter Institute EMMI and Research Division, GSI Helmholtzzentrum fuer Schwerionenforschung, 64291 Darmstadt (Germany); Winters, D.; Winters, N.; Yin, Z. [Helmholtzzentrum fuer Schwerionenforschung GSI, 64291 Darmstadt (Germany)

    2012-12-15T23:59:59.000Z

    We report on an experiment irradiating individual argon droplets of 20 {mu}m diameter with laser pulses of several Joule energy at intensities of 10{sup 19} W/cm{sup 2}. K-shell emission spectroscopy was employed to determine the hot electron energy fraction and the time-integrated charge-state distribution. Spectral fitting indicates that bulk temperatures up to 160 eV are reached. Modelling of the hot-electron relaxation and generation of K-shell emission with collisional hot-electron stopping only is incompatible with the experimental results, and the data suggest an additional ultra-fast (sub-ps) heating contribution. For example, including resistive heating in the modelling yields a much better agreement with the observed final bulk temperature and qualitatively reproduces the observed charge state distribution.

  14. Ultrafast high strain rate acoustic wave measurements at high static pressure in a diamond anvil cell

    SciTech Connect (OSTI)

    Armstrong, M; Crowhurst, J; Reed, E; Zaug, J

    2008-02-04T23:59:59.000Z

    We have used sub-picosecond laser pulses to launch ultra-high strain rate ({approx} 10{sup 9} s{sup -1}) nonlinear acoustic waves into a 4:1 methanol-ethanol pressure medium which has been precompressed in a standard diamond anvil cell. Using ultrafast interferometry, we have characterized acoustic wave propagation into the pressure medium at static compression up to 24 GPa. We find that the velocity is dependent on the incident laser fluence, demonstrating a nonlinear acoustic response which may result in shock wave behavior. We compare our results with low strain, low strain-rate acoustic data. This technique provides controlled access to regions of thermodynamic phase space that are otherwise difficult to obtain.

  15. Efficient Photoionization-Loading of Trapped Cadmium Ions with Ultrafast Pulses

    E-Print Network [OSTI]

    L. Deslauriers; M. Acton; B. B. Blinov; K. -A. Brickman; P. C. Haljan; W. K. Hensinger; D. Hucul; S. Katnik; R. N. Kohn, Jr.; P. J. Lee; M. J. Madsen; P. Maunz; S. Olmschenk; D. L. Moehring; D. Stick; J. Sterk; M. Yeo; K. C. Younge; C. Monroe

    2006-08-04T23:59:59.000Z

    Atomic cadmium ions are loaded into radiofrequency ion traps by photoionization of atoms in a cadmium vapor with ultrafast laser pulses. The photoionization is driven through an intermediate atomic resonance with a frequency-quadrupled mode-locked Ti:Sapphire laser that produces pulses of either 100 fsec or 1 psec duration at a central wavelength of 229 nm. The large bandwidth of the pulses photoionizes all velocity classes of the Cd vapor, resulting in high loading efficiencies compared to previous ion trap loading techniques. Measured loading rates are compared with a simple theoretical model, and we conclude that this technique can potentially ionize every atom traversing the laser beam within the trapping volume. This may allow the operation of ion traps with lower levels of background pressures and less trap electrode surface contamination. The technique and laser system reported here should be applicable to loading most laser-cooled ion species.

  16. Four-level atomic interferometer driven by shaped ultrafast laser pulses

    SciTech Connect (OSTI)

    Clow, Stephen; Weinacht, Thomas [Department of Physics, Stony Brook University, Stony Brook, New York 11794 (United States)

    2010-08-15T23:59:59.000Z

    We analyze the behavior of a four-state, two-path atomic interferometer driven by shaped ultrafast laser pulses. The laser pulses interact with atomic rubidium, exciting the atoms to the 5D state via two intermediate resonances (the 5P{sub 1/2} and 5P{sub 3/2}). The relative phase of the two paths can be modified by applying a varying spectral phase at the wavelength corresponding to one of the resonant transitions for each pathway. We trace out the behavior of the system from the simplest case of weak-field excitation with resonant fields to strong-field excitation with a broadband source. Our measurements and analysis reveal that while interference is observed for all field strengths and spectral widths, the character of the interference changes substantially.

  17. Ultrafast terahertz-induced response of GeSbTe phase-change materials

    SciTech Connect (OSTI)

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

    2014-06-23T23:59:59.000Z

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

  18. Collinear, two-color optical Kerr effect shutter for ultrafast time-resolved imaging

    E-Print Network [OSTI]

    Purwar, Harsh; Rozé, Claude; Sedarsky, David; Blaisot, Jean-Bernard

    2015-01-01T23:59:59.000Z

    Imaging with ultrashort exposure times is generally achieved with a crossed-beam geometry. In the usual arrangement, an off-axis gating pulse induces birefringence in a medium exhibiting a strong Kerr response (commonly carbon disulfide) which is followed by a polarizer aligned to fully attenuate the on-axis imaging beam. By properly timing the gate pulse, imaging light experiences a polarization change allowing time-dependent transmission through the polarizer to form an ultrashort image. The crossed-beam system is effective in generating short gate times, however, signal transmission through the system is complicated by the crossing angle of the gate and imaging beams. This work presents a robust ultrafast time-gated imaging scheme based on a combination of type-I frequency doubling and a collinear optical arrangement in carbon disulfide. We discuss spatial effects arising from crossed-beam Kerr gating, and examine the imaging spatial resolution and transmission timing affected by collinear activation of th...

  19. An ultrafast angle-resolved photoemission apparatus for measuring complex materials

    SciTech Connect (OSTI)

    Smallwood, Christopher L.; Lanzara, Alessandra [Department of Physics, University of California, Berkeley, California 94720 (United States); Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Jozwiak, Christopher [Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Zhang Wentao [Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

    2012-12-15T23:59:59.000Z

    We present technical specifications for a high resolution time- and angle-resolved photoemission spectroscopy setup based on a hemispherical electron analyzer and cavity-dumped solid state Ti:sapphire laser used to generate pump and probe beams, respectively, at 1.48 and 5.93 eV. The pulse repetition rate can be tuned from 209 Hz to 54.3 MHz. Under typical operating settings the system has an overall energy resolution of 23 meV, an overall momentum resolution of 0.003 A{sup -1}, and an overall time resolution of 310 fs. We illustrate the system capabilities with representative data on the cuprate superconductor Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+{delta}}. The descriptions and analyses presented here will inform new developments in ultrafast electron spectroscopy.

  20. Phonon-Assisted Ultrafast Charge Separation in a Realistic PCBM Aggregate

    E-Print Network [OSTI]

    Samuel L. Smith; Alex W. Chin

    2014-06-25T23:59:59.000Z

    Organic solar cells must separate strongly bound electron-hole pairs into free charges. This is achieved at interfaces between electron donor and acceptor organic semiconductors. The most popular electron acceptor is the fullerene derivative PCBM. Electron-hole separation has been observed on femtosecond timescales, which is incompatible with conventional Marcus theories of organic transport. In this work we show that ultrafast charge transport in PCBM arises from its broad range of electronic eigenstates, provided by the presence of three closely spaced delocalised bands near the LUMO level. Vibrational fluctuations enable rapid transitions between these bands, which drives an electron transport of $\\sim$3 nm within 100 fs. All this is demonstrated within a realistic tight binding Hamiltonian containing transfer integrals no larger than 8 meV.

  1. Efficient terahertz-wave generation and its ultrafast optical modulation in charge ordered organic ferroelectrics

    SciTech Connect (OSTI)

    Itoh, Hirotake, E-mail: hiroitoh@m.tohoku.ac.jp; Iwai, Shinichiro, E-mail: s-iwai@m.tohoku.ac.jp [Department of Physics, Tohoku University, Sendai 980-8578 (Japan); JST, CREST, Sendai 980-8578 (Japan); Itoh, Keisuke; Goto, Kazuki [Department of Physics, Tohoku University, Sendai 980-8578 (Japan); Yamamoto, Kaoru [Department of Applied Physics, Okayama University of Science, Okayama 700-0005 (Japan); Yakushi, Kyuya [Toyota Physical and Chemical Research Institute, Nagakute 480-1192 (Japan)

    2014-04-28T23:59:59.000Z

    Efficient terahertz (THz) wave generation in strongly correlated organic compounds ?-(ET){sub 2}I{sub 3} and ??-(ET){sub 2}IBr{sub 2} (ET:bis(ethylenedithio)-tetrathiafulvalene) was demonstrated. The spontaneous polarization induced by charge ordering or electronic ferroelectricity was revealed to trigger the THz-wave generation via optical rectification; the estimated 2nd-order nonlinear optical susceptibility for ?-(ET){sub 2}I{sub 3} is over 70 times larger than that for prototypical THz-source ZnTe. Ultrafast (<1 ps) and sensitive (?40%) photoresponse of the THz wave was observed for ?-(ET){sub 2}I{sub 3}, which is attributable to photoinduced quenching of the polarization accompanied by insulator(ferroelectric)-to-metal transition. Modulation of the THz wave was observed for ??-(ET){sub 2}IBr{sub 2} upon the poling procedure, indicating the alignment of polar domains.

  2. Ultrafast myoglobin structural dynamics observed with an X-ray free-electron laser

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

    Levantino, Matteo; Schirò, Giorgio; Lemke, Henrik Till; Cottone, Grazia; Glownia, James Michael; Zhu, Diling; Chollet, Mathieu; Ihee, Hyotcherl; Cupane, Antonio; Cammarata, Marco

    2015-04-02T23:59:59.000Z

    Light absorption can trigger biologically relevant protein conformational changes. The light induced structural rearrangement at the level of a photoexcited chromophore is known to occur in the femtosecond timescale and is expected to propagate through the protein as a quake-like intramolecular motion. Here we report direct experimental evidence of such ‘proteinquake’ observed in myoglobin through femtosecond X-ray solution scattering measurements performed at the Linac Coherent Light Source X-ray free-electron laser. An ultrafast increase of myoglobin radius of gyration occurs within 1 picosecond and is followed by a delayed protein expansion. As the system approaches equilibrium it undergoes damped oscillations withmore »a ~3.6-picosecond time period. Our results unambiguously show how initially localized chemical changes can propagate at the level of the global protein conformation in the picosecond timescale.« less

  3. A microfluidic flow-cell for the study of the ultrafast dynamics of biological systems

    SciTech Connect (OSTI)

    Chauvet, Adrien, E-mail: adrien.chauvet@epfl.ch; Chergui, Majed [Ecole Polytechnique Fédérale de Lausanne (EPFL), Laboratoire de Spectroscopie Ultrarapide, ISIC, Faculté des Sciences de Base, Station 6, 1015 Lausanne (Switzerland); Tibiletti, Tania; Caffarri, Stefano [Aix Marseille Université, CNRS, CEA, UMR 7265 Biologie Végétale et Microbiologie Environnementales, 13009 Marseille (France)

    2014-10-15T23:59:59.000Z

    The study of biochemical dynamics by ultrafast spectroscopic methods is often restricted by the limited amount of liquid sample available, while the high repetition rate of light sources can induce photodamage. In order to overcome these limitations, we designed a high flux, sub-ml, capillary flow-cell. While the 0.1 mm thin window of the 0.5 mm cross-section capillary ensures an optimal temporal resolution and a steady beam deviation, the cell-pump generates flows up to ?0.35 ml/s that are suitable to pump laser repetition rates up to ?14 kHz, assuming a focal spot-diameter of 100 ?m. In addition, a decantation chamber efficiently removes bubbles and allows, via septum, for the addition of chemicals while preserving the closed atmosphere. The minimal useable amount of sample is ?250 ?l.

  4. Ultra-fast heralded single photon source based on telecom technology

    E-Print Network [OSTI]

    Lutfi Arif Ngah; Olivier Alibart; Laurent Labonté; Virginia D'Auria; Sébastien Tanzilli

    2014-12-17T23:59:59.000Z

    The realization of an ultra-fast source of heralded single photons emitted at the wavelength of 1540 nm is reported. The presented strategy is based on state-of-the-art telecom technology, combined with off-the-shelf fiber components and waveguide non-linear stages pumped by a 10 GHz repetition rate laser. The single photons are heralded at a rate as high as 2.1 MHz with a heralding efficiency of 42%. Single photon character of the source is inferred by measuring the second-order autocorrelation function. For the highest heralding rate, a value as low as 0.023 is found. This not only proves negligible multi-photon contributions but also represents the best measured value reported to date for heralding rates in the MHz regime. These prime performances, associated with a device-like configuration, are key ingredients for both fast and secure quantum communication protocols.

  5. Ultra-fast photoluminescence as a diagnostic for laser damage initiation

    SciTech Connect (OSTI)

    Laurence, T A; Bude, J D; Shen, N; Miller, P E; Steele, W A; Guss, G; Adams, J J; Wong, L L; Feit, M D; Suratwala, T I

    2009-10-30T23:59:59.000Z

    Using high-sensitivity confocal time-resolved photoluminescence (CTP) techniques, we report an ultra-fast photoluminescence (40ps-5ns) from impurity-free surface flaws on fused silica, including polished, indented or fractured surfaces of fused silica, and from laser-heated evaporation pits. This fast photoluminescence (PL) is not associated with slower point defect PL in silica which has characteristic decay times longer than 5ns. Fast PL is excited by the single photon absorption of sub-band gap light, and is especially bright in fractures. Regions which exhibit fast PL are strongly absorptive well below the band gap, as evidenced by a propensity to damage with 3.5eV ns-scale laser pulses, making CTP a powerful non-destructive diagnostic for laser damage in silica. The use of CTP to provide insights into the nature of damage precursors and to help develop and evaluate new damage mitigation strategies will be presented.

  6. Molecular Science Computing | EMSL

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

    Scientific Capabilities Molecular Science Computing Overview Cell Isolation and Systems Analysis Deposition and Microfabrication Mass Spectrometry Microscopy Molecular Science...

  7. Ultrafast formation of the benzoic acid triplet upon ultraviolet photolysis and its sequential photodissociation in solution

    SciTech Connect (OSTI)

    Yang Chunfan; Su Hongmei [Beijing National Laboratory for Molecular Sciences (BNLMS), State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Sun Xuezhong; George, Michael W. [School of Chemistry, University of Nottingham, University Park NG7 2RD (United Kingdom)

    2012-05-28T23:59:59.000Z

    Time-resolved infrared (TR-IR) absorption spectroscopy in both the femtosecond and nanosecond time domain has been applied to examine the photolysis of benzoic acid in acetonitrile solution following either 267 nm or 193 nm excitation. By combining the ultrafast and nanosecond TR-IR measurements, both the excited states and the photofragments have been detected and key mechanistic insights were obtained. We show that the solvent interaction modifies the excited state relaxation pathways and thus the population dynamics, leading to different photolysis behavior in solution from that observed in the gas phase. Vibrational energy transfer to solvents dissipates excitation energy efficiently, suppressing the photodissociation and depopulating the excited S{sub 2} or S{sub 3} state molecules to the lowest T{sub 1} state with a rate of {approx}2.5 ps after a delayed onset of {approx}3.7 ps. Photolysis of benzoic acid using 267 nm excitation is dominated by the formation of the T{sub 1} excited state and no photofragments could be detected. The results from TR-IR experiments using higher energy of 193 nm indicate that photodissociation proceeds more rapidly than the vibrational energy transfer to solvents and C-C bond fission becomes the dominant relaxation pathway in these experiments as featured by the prominent observation of the COOH photofragments and negligible yield of the T{sub 1} excited state. The measured ultrafast formation of T{sub 1} excited state supports the existence of the surface intersections of S{sub 2}/S{sub 1}, S{sub 2}/T{sub 2}, and S{sub 1}/T{sub 1}/T{sub 2}, and the large T{sub 1} quantum yield of {approx}0.65 indicates the importance of the excited state depopulation to triplet manifold as the key factor affecting the photophysical and photochemical behavior of the monomeric benzoic acid.

  8. Dynamics of the plumes produced by ultrafast laser ablation of metals

    SciTech Connect (OSTI)

    Donnelly, T.; Lunney, J. G. [School of Physics, Trinity College Dublin, Dublin 2 (Ireland); Amoruso, S.; Bruzzese, R.; Wang, X. [Dipartimento di Scienze Fisiche and CNR-SPIN, Universita degli Studi di Napoli Federico II, Complesso Universitario di Monte S. Angelo, Via Cintia, I-80126 Napoli (Italy); Ni, X. [Department of Electronic Engineering, Tianjin University of Technology and Education, Tianjin 300222 (China)

    2010-08-15T23:59:59.000Z

    We have analyzed ultrafast laser ablation of a metallic target (Nickel) in high vacuum addressing both expansion dynamics of the various plume components (ionic and nanoparticle) and basic properties of the ultrafast laser ablation process. While the ion temporal profile and ion angular distribution were analyzed by means of Langmuir ion probe technique, the angular distribution of the nanoparticulate component was characterized by measuring the thickness map of deposition on a transparent substrate. The amount of ablated material per pulse was found by applying scanning white light interferometry to craters produced on a stationary target. We have also compared the angular distribution of both the ionic and nanoparticle components with the Anisimov model. While the agreement for the ion angular distribution is very good at any laser fluence (from ablation threshold up to {approx_equal}1 J/cm{sup 2}), some discrepancies of nanoparticle plume angular distribution at fluencies above {approx_equal}0.4 J/cm{sup 2} are interpreted in terms of the influence of the pressure exerted by the nascent atomic plasma plume on the initial hydrodynamic evolution of the nanoparticle component. Finally, analyses of the fluence threshold and maximum ablation depth were also carried out, and compared to predictions of theoretical models. Our results indicate that the absorbed energy is spread over a length comparable with the electron diffusion depth L{sub c} ({approx_equal}30 nm) of Ni on the timescale of electron-phonon equilibration and that a logarithmic dependence is well-suited for the description of the variation in the ablation depth on laser fluence in the investigated range.

  9. @Why Physics Comprehensive Physics Major.

    E-Print Network [OSTI]

    Yoo, S. J. Ben

    @Why Physics Comprehensive Physics Major. From the basic laws of physics to the resulting emergent behavior, physics studies what the universe is made of and how it works. As a Physics major that surrounds us, to the structure and evolution of the entire universe. We offer three degrees in Physics

  10. Frequency modulated few-cycle optical pulse trains induced controllable ultrafast coherent population oscillations in three-level atomic systems

    E-Print Network [OSTI]

    Parvendra Kumar; Amarendra K. Sarma

    2012-11-16T23:59:59.000Z

    We report a study on the ultrafast coherent population oscillations (UCPO) in two level atoms induced by the frequency modulated few-cycle optical pulse train. The phenomenon of UCPO is investigated by numerically solving the optical Bloch equations beyond the rotating wave approximation. We demonstrate that the quantum state of the atoms and the frequency of UCPO may be controlled by controlling the number of pulses in the pulse trains and the pulse repetition time respectively. Moreover, the robustness of the population inversion against the variation of the laser pulse parameters is also investigated. The proposed scheme may be useful for the creation of atoms in selected quantum state for desired time duration and may have potential applications in ultrafast optical switching.

  11. 650-nJ pulses from a cavity-dumped Yb:fiber-pumped ultrafast optical parametric oscillator

    E-Print Network [OSTI]

    650-nJ pulses from a cavity-dumped Yb:fiber- pumped ultrafast optical parametric oscillator Tobias.p.lamour@hw.ac.uk Abstract: Sub-250-fs pulses with energies of up to 650 nJ and peak powers up to 2.07 MW were generated from a cavity-dumped optical parametric oscillator, synchronously-pumped at 15.3 MHz with sub-400-fs pulses from

  12. 2012 ATOMIC AND MOLECULAR INTERACTIONS GORDON RESEARCH CONFERENCE AND GORDON RESEARCH SEMINAR, JULY 15-20, 2012

    SciTech Connect (OSTI)

    Zwier, Timothy

    2012-07-20T23:59:59.000Z

    At the 2012 Atomic and Molecular Interactions Gordon Conference, there will be talks in several broadly defined and partially overlapping areas: ? Intramolecular and single-collision reaction dynamics; ? Photophysics and photochemistry of excited states; ? Clusters, aerosols and solvation; ? Interactions at interfaces; ? Conformations and folding of large molecules; ? Interactions under extreme conditions of temperature and pressure. The theme of the Gordon Research Seminar on Atomic & Molecular Interactions, in keeping with the tradition of the Atomic and Molecular Interactions Gordon Research Conference, is far-reaching and involves fundamental research in the gas and condensed phases along with application of these ideas to practical chemical fields. The oral presentations, which will contain a combination of both experiment and theory, will focus on four broad categories: ? Ultrafast Phenomena; ? Excited States, Photoelectrons, and Photoions; ? Chemical Reaction Dynamics; ? Biomolecules and Clusters.

  13. Industrial Affiliates Day 2006, April 21, 2006 ULTRAFAST NONLINEAR OPTICAL MICROSCOPY

    E-Print Network [OSTI]

    Van Stryland, Eric

    of studies, including photochemical reactions, molecular dynamics, micropharmacology and optical memory. History of Two-Photon Molecular Excitation 1905 First Conception: A. Einstein: Creation and Conversion for data storage. Combined with fluorescence microscopy, multiphoton excitation (MPE) provides 3D

  14. Molecular Foundry

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742EnergyOnItemResearch > The EnergyCenterDioxide Capture inFacility AMFInnovationMolecularOne of

  15. Molecular Foundry

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742EnergyOnItemResearch > The EnergyCenterDioxide Capture inFacility AMFInnovationMolecularOne

  16. Molecular Foundry

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742EnergyOnItemResearch > The EnergyCenterDioxide Capture inFacility AMFInnovationMolecularOneThe

  17. Quantum physics motivated neurobiology

    E-Print Network [OSTI]

    Mershin, Andreas

    2000-01-01T23:59:59.000Z

    to finding out how the external world is coded in the microscopic structure of the brain and eventually, we will be able to appreciate how unique experiences make unique individuals even though the basic genetic, molecular and physical processes are shared...' . The close rehtionship of the nerve cells and the neuroglia is evidenced by tbe fact that neurons do not grow and thrive in tissue culture unless neuroglial cells are also present. Recent findings suggest the "tripartite model" for synapses where glial...

  18. Planetary, Atmospheric, and Environmental Applications of Physics Frank Mills

    E-Print Network [OSTI]

    Chen, Ying

    Planetary, Atmospheric, and Environmental Applications of Physics Frank Mills Atomic and Molecular solar energy production Evaluating, forecasting, and managing suburb-scale distributed solar electricity production My research applies physics to a range of problems in planetary, atmospheric, and environmental

  19. DEPARTMENT OF PHYSICS Physics 42200

    E-Print Network [OSTI]

    Lombardi, John R.

    DEPARTMENT OF PHYSICS Syllabus Physics 42200 Biophysics Designation: Undergraduate Catalog and membranes. In depth study of the physical basis of selected systems including vision, nerve transmission. Prerequisites: Prereq.: 1 yr. of Math, 1 yr. of Physics (elective for Physics Majors and Biomedical Engineering

  20. DEPARTMENT OF PHYSICS Physics 32300

    E-Print Network [OSTI]

    Lombardi, John R.

    DEPARTMENT OF PHYSICS Syllabus Physics 32300 Quantum Mechanics for Engineers Designation: required for Physics majors in the Applied Physics Option Undergraduate Catalog description: Basic experiments, wave: Physics 20700 and 20800, Math 39100 and Math 39200 Textbook and other suggested material: Scherrer

  1. Physics and Astronomy Department Strategic Plan March 1, 2011

    E-Print Network [OSTI]

    Harms, Kyle E.

    Physics and Astronomy Department Strategic Plan March 1, 2011 Executive Summary The Department of Physics & Astronomy performs world-class research and provides state-of-the-art training for students in astronomy, astrophysics, and gravitational physics; atomic/molecular/optical physics, quantum optics

  2. Molecular Science Computing | EMSL

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

    Molecular Science Computing Overview Cell Isolation and Systems Analysis Deposition and Microfabrication Mass Spectrometry Microscopy Molecular Science Computing NMR and EPR...

  3. Ultrafast control of donor-bound electron spins with single detuned optical pulses

    E-Print Network [OSTI]

    Kai-Mei C. Fu; Susan M. Clark; Charles Santori; M. C. Holland; Colin R. Stanley; Yoshihisa Yamamoto

    2008-06-25T23:59:59.000Z

    The ability to control spins in semiconductors is important in a variety of fields including spintronics and quantum information processing. Due to the potentially fast dephasing times of spins in the solid state [1-3], spin control operating on the picosecond or faster timescale may be necessary. Such speeds, which are not possible to attain with standard electron spin resonance (ESR) techniques based on microwave sources, can be attained with broadband optical pulses. One promising ultrafast technique utilizes single broadband pulses detuned from resonance in a three-level Lambda system [4]. This attractive technique is robust against optical pulse imperfections and does not require a fixed optical reference phase. Here we demonstrate the principle of coherent manipulation of spins theoretically and experimentally. Using this technique, donor-bound electron spin rotations with single-pulse areas exceeding pi/4 and two-pulses areas exceeding pi/2 are demonstrated. We believe the maximum pulse areas attained do not reflect a fundamental limit of the technique and larger pulse areas could be achieved in other material systems. This technique has applications from basic solid-state ESR spectroscopy to arbitrary single-qubit rotations [4, 5] and bang-bang control[6] for quantum computation.

  4. Surface modified CFx cathode material for ultrafast discharge and high energy density

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

    Dai, Yang [Shanghai Inst. of Space Power Sources, Shanghai (China); Zhu, Yimei [Brookhaven National Lab. (BNL), Upton, NY (United States); Cai, Sendan [Shanghai Inst. of Space Power Sources, Shanghai (China); Wu, Lijun [Brookhaven National Lab. (BNL), Upton, NY (United States); Yang, Weijing [Shanghai Inst. of Space Power Sources, Shanghai (China); Xie, Jingying [Shanghai Inst. of Space Power Sources, Shanghai (China); Shanghai Engineering Center for Power and Energy Storage Systems, Shanghai (China); Wen, Wen [BL14B1 Shanghai Synchrotron Radiation Facility, Shanghai (China); Zheng, Jin-Cheng [Xiamen Univ., Xiamen (China); Zheng, Yi [Shanghai Inst. of Space Power Sources, Shanghai (China)

    2014-01-01T23:59:59.000Z

    Li/CFx primary possesses the highest energy density of 2180 W h kg?¹ among all primary lithium batteries. However, a key limitation for the utility of this type of battery is in its poor rate capability because the cathode material, CFx, is an intrinsically poor electronic conductor. Here, we report on our development of a controlled process of surface de-fluorination under mild hydrothermal conditions to modify the highly fluorinated CFx. The modified CFx, consisting of an in situ generated shell component of F-graphene layers, possesses good electronic conductivity and removes the transporting barrier for lithium ions, yielding a high-capacity performance and an excellent rate-capability. Indeed, a capacity of 500 mA h g?¹ and a maximum power density of 44 800 W kg?¹ can be realized at the ultrafast rate of 30 C (24 A g?¹), which is over one order of magnitude higher than that of the state-of-the-art primary lithium-ion batteries.

  5. Surface modified CFx cathode material for ultrafast discharge and high energy density

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

    Dai, Yang; Zhu, Yimei; Cai, Sendan; Wu, Lijun; Yang, Weijing; Xie, Jingying; Wen, Wen; Zheng, Jin-Cheng; Zheng, Yi

    2014-01-01T23:59:59.000Z

    Li/CFx primary possesses the highest energy density of 2180 W h kg?¹ among all primary lithium batteries. However, a key limitation for the utility of this type of battery is in its poor rate capability because the cathode material, CFx, is an intrinsically poor electronic conductor. Here, we report on our development of a controlled process of surface de-fluorination under mild hydrothermal conditions to modify the highly fluorinated CFx. The modified CFx, consisting of an in situ generated shell component of F-graphene layers, possesses good electronic conductivity and removes the transporting barrier for lithium ions, yielding a high-capacity performance andmore »an excellent rate-capability. Indeed, a capacity of 500 mA h g?¹ and a maximum power density of 44 800 W kg?¹ can be realized at the ultrafast rate of 30 C (24 A g?¹), which is over one order of magnitude higher than that of the state-of-the-art primary lithium-ion batteries.« less

  6. Ultrafast Manipulation of a Double Quantum Dot via Lyapunov Control Method

    E-Print Network [OSTI]

    Shuang Cong; Ming-yong Gao; Long-zhen Hu; Guo-ping Guo; Gang Cao; Guang-can Guo

    2014-01-12T23:59:59.000Z

    For a double quantum dot (DQD) system, here we propose alternative ultrafast manipulate approach: Lyapunov control method, to transfer the state from R to L on the picosecond scale, orders of magnitude faster and transfer probability higher than the previously measured electrically controlled charge- or spin-based quits. The control laws are composed of two-direction components, one is used to eliminate the dissipation in the system, another is used to transfer the state. The control theory's stability ensures the system can be transferred to the target state in high probability, and the coefficients in control laws leads very fast convergence. The role of eliminating the dissipation plays the suppression of decoherence effect. Numerical simulation results show that under the realistic implementation conditions, the transfer probability and fidelity can be increased up to 98.79% and 98.97%, respectively. This is the first result directly applicable to a DQD system's state transferring using the Lyapunov control method. We also give specific experimental realization scheme.

  7. On the presence of ultra-fast outflows in the WAX sample of Seyfert galaxies

    E-Print Network [OSTI]

    Tombesi, Francesco

    2014-01-01T23:59:59.000Z

    The study of winds in active galactic nuclei (AGN) is of utmost importance as they may provide the long sought-after link between the central black hole and the host galaxy, establishing the AGN feedback. Recently, Laha et al. (2014) reported the X-ray analysis of a sample of 26 Seyferts observed with XMM-Newton, which are part of the so-called warm absorbers in X-rays (WAX) sample. They claim the non-detection of Fe K absorbers indicative of ultra-fast outflows (UFOs) in four observations previously analyzed by Tombesi et al. (2010). They mainly impute the Tombesi et al. detections to an improper modeling of the underlying continuum in the E=4-10 keV band. We therefore re-address here the robustness of these detections and we find that the main reason for the claimed non-detections is likely due to their use of single events only spectra, which reduces the total counts by 40%. Performing a re-analysis of the data in the whole E=0.3-10 keV energy band using their models and spectra including also double event...

  8. HELIOS-K: An Ultrafast, Open-source Opacity Calculator for Radiative Transfer

    E-Print Network [OSTI]

    Grimm, Simon L

    2015-01-01T23:59:59.000Z

    We present an ultrafast opacity calculator for application to exoplanetary atmospheres, which we name HELIOS-K. It takes a line list as an input, computes the shape of each spectral line (e.g., a Voigt profile) and provides an option for grouping an enormous number of lines into a manageable number of bins. We implement a combination of Algorithm 916 and Gauss-Hermite quadrature to compute the Voigt profile, write the code in CUDA and optimise the computation for graphics processing units (GPUs). We use the k-distribution method to reduce $\\sim 10^5$ to $10^8$ lines to $\\sim 10$ to $10^4$ wavenumber bins, which may then be used for radiative transfer, atmospheric retrieval and general circulation models. We demonstrate that the resampling of the k-distribution function, within each bin, is an insignificant source of error across a broad range of wavenumbers and column masses. By contrast, the choice of line-wing cutoff for the Voigt profile is a significant source of error and affects the value of the compute...

  9. Velocity measurements in the near field of a diesel fuel injector by ultrafast imagery

    E-Print Network [OSTI]

    Sedarsky, David; Blaisot, Jean-Bernard; Rozé, Claude

    2013-01-01T23:59:59.000Z

    This paper examines the velocity profile of fuel issuing from a high-pressure single-orifice diesel injector. Velocities of liquid structures were determined from time-resolved ultrafast shadow images, formed by an amplified two-pulse laser source coupled to a double-frame camera. A statistical analysis of the data over many injection events was undertaken to map velocities related to spray formation near the nozzle outlet as a function of time after start of injection. These results reveal a strong asymmetry in the liquid profile of the test injector, with distinct fast and slow regions on opposite sides of the orifice. Differences of ~100 m/s can be observed between the 'fast' and 'slow' sides of the jet, resulting in different atomization conditions across the spray. On average, droplets are dispersed at a greater distance from the nozzle on the 'fast' side of the flow, and distinct macrostructure can be observed under the asymmetric velocity conditions. The changes in structural velocity and atomization b...

  10. Solution Processed MoS2-PVA Composite for Sub-Bandgap Mode-Locking of a Wideband Tunable Ultrafast Er:Fiber Laser

    E-Print Network [OSTI]

    Zhang, Meng; Howe, Richard C. T.; Woodward, Robert I.; Kelleher, Edmund J. R.; Torrisi, Felice; Hu, Guohua; Popov, Sergei V.; Taylor, J. Roy; Hasan, Tawfique

    2014-11-11T23:59:59.000Z

    with stable, picosecond pulses, tunable from 1535 nm to 1565 nm 2 Solution Processed MoS2-PVA Composite for Sub-Bandgap Mode-Locking of a Wideband Tunable Ultrafast Er:Fiber Laser Meng Zhang1, Richard C. T. Howe2, Robert I. Woodward1... ! to! relaxation! of! thermalized! electron! and!phonon! distribution! [3].! This! combination! of!properties!makes!MoS2!a!suitable!saturable!absorber!(SA)! for! ultrafast! mode+locked! pulsed! lasers,! with!the! potential! for! pulse! generation! at...

  11. Molecular weight and molecular weight distribution of kraft lignins

    SciTech Connect (OSTI)

    Schmidl, W.; Dong, D.; Fricke, A.L. (Univ. of Florida, Gainesville, FL (United States))

    1990-01-01T23:59:59.000Z

    Kraft lignins are the lignin degradation products from kraft pulping. They are complex, heterogeneous polymers with some polar character. The molecular weight of kraft lignins greatly affect the physical properties of black liquors, and are of primary importance in separation from black liquor and in evaluating potential uses. Several purified kraft lignins from slash pine were analyzed for number average molecular weight by vapor pressure osmometry (VPO), for weight average molecular weight by low angle laser light scattering (LALLS), and for the molecular weight distribution by high temperature size exclusion chromatography (SEC). The lignins were run in tetrahydrofuran (THF), N,N-dimethyl formamide (DMF), DMF with 0.1M LiBr, and pyridine at conditions above the Theta temperature. Experimental methods are discussed. The results show that VPO may be used to determine M[sub n] for kraft lignins if the purity of the lignins and the identity of the impurities are known. LALLS can be used to determine M[sub w] for kraft lignins if measurements are made at or above the Theta temperature of the lignin-solvent pair. SEC should be used at temperatures at, or above, the Theta temperature of the lignin-solvent pair. Size separation is highly dependent on the solvent used, and DMF is a much better solvent than THF for high temperature SEC. Future work using moment resolution procedures to derive an accurate calibration curve are also discussed.

  12. Electron diffraction using ultrafast electron bunches from a laser-wakefield accelerator at kHz repetition rate

    SciTech Connect (OSTI)

    He, Z.-H.; Thomas, A. G. R.; Nees, J. A.; Hou, B.; Krushelnick, K. [Center for Ultrafast Optical Science, University of Michigan, Ann Arbor, Michigan 48106-2099 (United States)] [Center for Ultrafast Optical Science, University of Michigan, Ann Arbor, Michigan 48106-2099 (United States); Beaurepaire, B.; Malka, V.; Faure, J. [Laboratoire d'Optique Appliquee, ENSTA-CNRS-Ecole Polytechnique, UMR 7639, 91761 Palaiseau (France)] [Laboratoire d'Optique Appliquee, ENSTA-CNRS-Ecole Polytechnique, UMR 7639, 91761 Palaiseau (France)

    2013-02-11T23:59:59.000Z

    We show that electron bunches in the 50-100 keV range can be produced from a laser wakefield accelerator using 10 mJ, 35 fs laser pulses operating at 0.5 kHz. It is shown that using a solenoid magnetic lens, the electron bunch distribution can be shaped. The resulting transverse and longitudinal coherence is suitable for producing diffraction images from a polycrystalline 10 nm aluminum foil. The high repetition rate, the stability of the electron source, and the fact that its uncorrelated bunch duration is below 100 fs make this approach promising for the development of sub-100 fs ultrafast electron diffraction experiments.

  13. Ultrafast and selective coherent population transfer in four-level atoms by a single frequency chirped few-cycle pulse

    E-Print Network [OSTI]

    Parvendra Kumar; Amarendra K. Sarma

    2013-03-01T23:59:59.000Z

    We report and propose a simple scheme to achieve the ultrafast and selective population transfer in four-level atoms by utilizing a single frequency chirped few-cycle pulse. It is demonstrated that the almost complete population may be transferred to the preselected state of atoms just by manipulating the so called chirp offset parameter. The robustness of the scheme against the variation of laser pulse parameters is also investigated. The proposed scheme may also be useful for the selective population transfer in molecules.

  14. Ultrafast and efficient coherence creation in ?-like atomic systems driven by nonlinearly chirped few-cycle pulses

    E-Print Network [OSTI]

    Amarendra K. Sarma; Parvendra Kumar

    2011-11-17T23:59:59.000Z

    We report an ultrafast and efficient way to create the maximum coherence between the two lower states in a -like atomic systems, driven by two nonlinearly chirped few-cycle pulses. The phenomenon of coherent population trapping and electromagnetically induced population transfer are investigated by solving the appropriate density matrix equations without invoking the rotating wave approximation. The robustness of the scheme for maximum coherence against the variation of the laser parameters are tested numerically. We also demonstrate that the proposed scheme could be used to obtain complete population transfer to an initially empty ground state.

  15. accurate dynamic molecular: Topics by E-print Network

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

    18 19 20 21 22 23 24 25 Next Page Last Page Topic Index 1 How accurate is molecular dynamics? Mathematical Physics (arXiv) Summary: Born-Oppenheimer dynamics is shown to provide...

  16. Symposium on molecular and cellular mechanisms of mutagenesis

    SciTech Connect (OSTI)

    Not Available

    1981-01-01T23:59:59.000Z

    These proceedings contain abstracts only of the 21 papers presented at the Sympsoium. The papers dealt with molecular mechanisms of mutagenesis and cellular responses to chemical and physical mutagenic agents. (ERB)

  17. Role of electron-electron interference in ultrafast time-resolved imaging of electronic wavepackets

    SciTech Connect (OSTI)

    Dixit, Gopal [Center for Free-Electron Laser Science, DESY, Notkestrasse 85, D-22607 Hamburg (Germany); Santra, Robin [Center for Free-Electron Laser Science, DESY, Notkestrasse 85, D-22607 Hamburg (Germany); Department of Physics, University of Hamburg, D-20355 Hamburg (Germany)

    2013-04-07T23:59:59.000Z

    Ultrafast time-resolved x-ray scattering is an emerging approach to image the dynamical evolution of the electronic charge distribution during complex chemical and biological processes in real-space and real-time. Recently, the differences between semiclassical and quantum-electrodynamical (QED) theory of light-matter interaction for scattering of ultrashort x-ray pulses from the electronic wavepacket were formally demonstrated and visually illustrated by scattering patterns calculated for an electronic wavepacket in atomic hydrogen [G. Dixit, O. Vendrell, and R. Santra, Proc. Natl. Acad. Sci. U.S.A. 109, 11636 (2012)]. In this work, we present a detailed analysis of time-resolved x-ray scattering from a sample containing a mixture of non-stationary and stationary electrons within both the theories. In a many-electron system, the role of scattering interference between a non-stationary and several stationary electrons to the total scattering signal is investigated. In general, QED and semiclassical theory provide different results for the contribution from the scattering interference, which depends on the energy resolution of the detector and the x-ray pulse duration. The present findings are demonstrated by means of a numerical example of x-ray time-resolved imaging for an electronic wavepacket in helium. It is shown that the time-dependent scattering interference vanishes within semiclassical theory and the corresponding patterns are dominated by the scattering contribution from the time-independent interference, whereas the time-dependent scattering interference contribution do not vanish in the QED theory and the patterns are dominated by the scattering contribution from the non-stationary electron scattering.

  18. Ultrafast heterogeneous electron transfer reactions: Comparative theoretical studies on time- and frequency-domain data

    SciTech Connect (OSTI)

    Wang Luxia; Willig, Frank; May, Volkhard [Institut fuer Physik, Humboldt-Universitaet zu Berlin, Newtonstrasse 15, D-12489 Berlin (Germany); Hahn-Meitner-Institut, Abteilung Dynamik von Genzflaechenreaktionen, Glienicker Strasse 100, 14109 Berlin (Germany); Institut fuer Physik, Humboldt-Universitaet zu Berlin, Newtonstrasse 15, D-12489 Berlin (Germany)

    2006-01-07T23:59:59.000Z

    Recent theoretical studies on linear absorption spectra of dye-semiconductor systems [perylene attached to nanostructured TiO{sub 2}, L. Wang et al., J. Phys. Chem. B 109, 9589 (2005)] are extended here in different respects. Since the systems show ultrafast photoinduced heterogeneous electron transfer the time-dependent formulation used to compute the absorbance is also applied to calculate the temporal evolution of the sub-100 fs charge injection dynamics after a 10 fs laser-pulse excitation. These studies complement our recent absorption spectra fit for two perylene bridge-anchor group TiO{sub 2} systems. Moreover, the time-dependent formulation of the absorbance is confronted with a frequency-domain description. The latter underlines the central importance of the self-energy caused by the coupling of the dye levels to the semiconductor band continuum. The used model is further applied to study the effect of different parameters such as (1) the dependence on the reorganization energies of the involved intramolecular transitions, (2) the effect of changing the transfer integral which couples the excited dye state with the band continuum, and (3) the effect of the concrete form of the semiconductor band density of states. Emphasis is also put on the case where the charge injection level of the dye is near or somewhat below the band edge. This nicely demonstrates the change from a structureless absorption to a well-resolved vibrational progression including characteristic shifts of the absorption lines which are a direct measure for the dye-semiconductor coupling.

  19. Ultrafast dark-field surface inspection with hybrid-dispersion laser scanning

    SciTech Connect (OSTI)

    Yazaki, Akio [Department of Electrical Engineering, University of California, Los Angeles, California 90095 (United States); Yokohama Research Laboratory, Hitachi, Ltd., Kanagawa 244-0817 (Japan); Kim, Chanju [Department of Electrical Engineering, University of California, Los Angeles, California 90095 (United States); Advanced Photonics Research Institute, Gwangju Institute of Science and Technology, Gwangju 500-712 (Korea, Republic of); Chan, Jacky [Department of Electrical Engineering, University of California, Los Angeles, California 90095 (United States); Mahjoubfar, Ata [Department of Electrical Engineering, University of California, Los Angeles, California 90095 (United States); California NanoSystems Institute, University of California, Los Angeles, California 90095 (United States); Goda, Keisuke, E-mail: goda@chem.s.u-tokyo.ac.jp [Department of Electrical Engineering, University of California, Los Angeles, California 90095 (United States); Department of Chemistry, University of Tokyo, Tokyo 113-0033 (Japan); Watanabe, Masahiro [Yokohama Research Laboratory, Hitachi, Ltd., Kanagawa 244-0817 (Japan); Jalali, Bahram [Department of Electrical Engineering, University of California, Los Angeles, California 90095 (United States); California NanoSystems Institute, University of California, Los Angeles, California 90095 (United States); Department of Bioengineering, University of California, Los Angeles, California 90095 (United States); Department of Surgery, David Geffen School of Medicine, University of California, Los Angeles, California 90095 (United States)

    2014-06-23T23:59:59.000Z

    High-speed surface inspection plays an important role in industrial manufacturing, safety monitoring, and quality control. It is desirable to go beyond the speed limitation of current technologies for reducing manufacturing costs and opening a new window onto a class of applications that require high-throughput sensing. Here, we report a high-speed dark-field surface inspector for detection of micrometer-sized surface defects that can travel at a record high speed as high as a few kilometers per second. This method is based on a modified time-stretch microscope that illuminates temporally and spatially dispersed laser pulses on the surface of a fast-moving object and detects scattered light from defects on the surface with a sensitive photodetector in a dark-field configuration. The inspector's ability to perform ultrafast dark-field surface inspection enables real-time identification of difficult-to-detect features on weakly reflecting surfaces and hence renders the method much more practical than in the previously demonstrated bright-field configuration. Consequently, our inspector provides nearly 1000 times higher scanning speed than conventional inspectors. To show our method's broad utility, we demonstrate real-time inspection of the surface of various objects (a non-reflective black film, transparent flexible film, and reflective hard disk) for detection of 10??m or smaller defects on a moving target at 20?m/s within a scan width of 25?mm at a scan rate of 90.9?MHz. Our method holds promise for improving the cost and performance of organic light-emitting diode displays for next-generation smart phones, lithium-ion batteries for green electronics, and high-efficiency solar cells.

  20. A Quadratic Assignment Formulation of the Molecular

    E-Print Network [OSTI]

    Neumaier, Arnold

    in molecular bio­ physics and biochemistry is the protein folding problem (Gierasch and King 1990). The protein­ tion concern. The value of computation of protein folding patterns is that although it is now quite conformation problem'' does not in itself solve the protein folding problem; however, this general approach

  1. Ultrafast Infrared Heating Laser Pulse-Induced Micellization Kinetics of Poly(ethylene oxide)-Poly(propylene oxide)-Poly(ethylene oxide) in

    E-Print Network [OSTI]

    Liu, Shilin

    Ultrafast Infrared Heating Laser Pulse-Induced Micellization Kinetics of Poly(ethylene oxide infrared heating laser pulse (10 ns)-induced temperature jump. The increases in the fluorescenceVersity of Hong Kong, Shatin N.T., Hong Kong ReceiVed June 4, 2007. In Final Form: July 7, 2007 The heating

  2. 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

  3. Use of Ultrafast Dispersed Pump-Dump-Probe and Pump-Repump-Probe Spectroscopies to Explore the Light-Induced Dynamics of Peridinin in Solution

    E-Print Network [OSTI]

    van Stokkum, Ivo

    Use of Ultrafast Dispersed Pump-Dump-Probe and Pump-Repump-Probe Spectroscopies to Explore Form: NoVember 14, 2005 Optical pump-induced dynamics of the highly asymmetric carotenoid peridinin in methanol was studied by dispersed pump-probe, pump-dump-probe, and pump-repump-probe transient absorption

  4. Single-pulse ultrafast-laser machining of high aspect nano-holes at the surface of SiO2

    E-Print Network [OSTI]

    Davis, Lloyd M.

    (2005). 6. T. N. Kim, K. Campbell, A. Groisman, D. Kleinfeld, and C. B. Schaffer, "Femtosecond laser-drilled, and D. Low, "Precision glass machining, drilling and profile cutting by short pulse lasers," Thin SolidSingle-pulse ultrafast-laser machining of high aspect nano-holes at the surface of SiO2 Yelena V

  5. Science Challenge Computational modeling of ultrafast digital electronics To understand how large electric fields, such as those from lightning strikes or electronic countermeasures,

    E-Print Network [OSTI]

    Freericks, Jim

    properties in response to the needs of a particular device or situation. These smart electronics have the potential to lead to entirely new generations of electronic devices--such as military and civilian Science Challenge ­ Computational modeling of ultrafast digital electronics · To understand how

  6. Transition from ultrafast laser photo-electron emission to space charge limited current in a 1D gap

    E-Print Network [OSTI]

    Yangjie Liu; L. K. Ang

    2014-08-21T23:59:59.000Z

    A one-dimensional (1D) model has been constructed to study the transition of the time-dependent ultrafast laser photo-electron emission from a flat metallic surface to the space charge limited (SCL) current, including the effect of non-equilibrium laser heating on metals at the ultrafast time scale. At a high laser field, it is found that the space charge effect cannot be ignored and the SCL current emission is reached at a lower value predicted by a short pulse SCL current model that assumed a time-independent emission process. The threshold of the laser field to reach the SCL regime is determined over a wide range of operating parameters. The calculated results agree well with particle-in-cell (PIC) simulation. It is found that the space charge effect is more important for materials with lower work function like tungsten (4.4 eV) as compared to gold (5.4 eV). However for a flat surface, both materials will reach the space charge limited regime at the sufficiently high laser field such as $>$ 5 GV/m with a laser pulse length of tens to one hundred femtoseconds.

  7. Control of molecular rotation in the limit of extreme rotational excitation

    E-Print Network [OSTI]

    V. Milner; J. W. Hepburn

    2015-01-12T23:59:59.000Z

    Laser control of molecular rotation is an area of active research. A number of recent studies has aimed at expanding the reach of rotational control to extreme, previously inaccessible rotational states, as well as controlling the directionality of molecular rotation. Dense ensembles of molecules undergoing ultrafast uni-directional rotation, known as molecular superrotors, are anticipated to exhibit unique properties, from spatially anisotropic diffusion and vortex formation to the creation of powerful acoustic waves and tuneable THz radiation. Here we describe our recent progress in controlling molecular rotation in the regime of high rotational excitation. We review two experimental techniques of producing uni-directional rotational wave packets with a "chiral train" of femtosecond pulses and an "optical centrifuge". Three complementary detection methods, enabling the direct observation, characterization and control of the superrotor states, are outlined: the one based on coherent Raman scattering, and two other methods employing both resonant and non-resonant multi-photon ionization. The capabilities of the described excitation and detection techniques are demonstrated with a few examples. The paper is concluded with an outlook for future developments.

  8. PHYSICAL REVIEW A 86, 033834 (2012) Compression, spectral broadening, and collimation in multiple, femtosecond pulse

    E-Print Network [OSTI]

    Milchberg, Howard

    2012-01-01T23:59:59.000Z

    PHYSICAL REVIEW A 86, 033834 (2012) Compression, spectral broadening, and collimation in multiple molecular alignment. Through the polarization density, the molecular alignment provides an index this contribution to the index, modifying the propagation of subsequent pulses. Here we present propagation

  9. Molecular information ratchets 

    E-Print Network [OSTI]

    Wilson, Adam Christopher

    2012-11-28T23:59:59.000Z

    In the emerging aield of molecular machines, a molecular ratchet is a chemical system that allows the positional displacement of a submolecular component of be captured and directionally relea ...

  10. EMSL - Molecular Science Computing

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

    computing Resources and Techniques Molecular Science Computing - Sophisticated and integrated computational capabilities, including scientific consultants, software, Cascade...

  11. LANL | Physics | High Energy Physics

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

    Exploring the intensity frontier On the trail of one of the greatest mysteries in physics, researchers on the Long Baseline Neutrino Experiment (LBNE) seek to discover why...

  12. DEPARTMENT OF PHYSICS Physics 35400

    E-Print Network [OSTI]

    Lombardi, John R.

    , electromagnetic waves in vacuum and in matter, guided waves ­ transmission lines and waveguides, electromagnetic-varying sources 7. calculate the electromagnetic radiation fields and power emitted for electric dipole sources 8DEPARTMENT OF PHYSICS Syllabus Physics 35400 Electricity and Magnetism II Designation

  13. Molecular Hydrogen Emission from Protoplanetary Disks

    E-Print Network [OSTI]

    H. Nomura; T. J. Millar

    2005-05-06T23:59:59.000Z

    We have modeled self-consistently the density and temperature profiles of gas and dust in protoplanetary disks, taking into account irradiation from a central star. Making use of this physical structure, we have calculated the level populations of molecular hydrogen and the line emission from the disks. As a result, we can reproduce the observed strong line spectra of molecular hydrogen from protoplanetary disks, both in the ultraviolet (UV) and the near-infrared, but only if the central star has a strong UV excess radiation.

  14. Molecular electrostatic potentials by systematic molecular fragmentation

    SciTech Connect (OSTI)

    Reid, David M.; Collins, Michael A. [Research School of Chemistry, Australian National University, Canberra, ACT 0200 (Australia)] [Research School of Chemistry, Australian National University, Canberra, ACT 0200 (Australia)

    2013-11-14T23:59:59.000Z

    A simple method is presented for estimating the molecular electrostatic potential in and around molecules using systematic molecular fragmentation. This approach estimates the potential directly from the electron density. The accuracy of the method is established for a set of organic molecules and ions. The utility of the approach is demonstrated by estimating the binding energy of a water molecule in an internal cavity in the protein ubiquitin.

  15. Role of surface states and defects in the ultrafast nonlinear optical properties of CuS quantum dots

    SciTech Connect (OSTI)

    Mary, K. A. Ann; Unnikrishnan, N. V., E-mail: nvu100@yahoo.com [School of Pure and Applied Physics, Mahatma Gandhi University, Kottayam 686560 (India); Philip, Reji [Light and Matter Physics Group, Raman Research Institute, C.V. Raman Avenue, Sadashivanagar, Bangalore 560080 (India)

    2014-07-01T23:59:59.000Z

    We report facile preparation of water dispersible CuS quantum dots (2–4 nm) and nanoparticles (5–11 nm) through a nontoxic, green, one-pot synthesis method. Optical and microstructural studies indicate the presence of surface states and defects (dislocations, stacking faults, and twins) in the quantum dots. The smaller crystallite size and quantum dot formation have significant effects on the high energy excitonic and low energy plasmonic absorption bands. Effective two-photon absorption coefficients measured using 100 fs laser pulses employing open-aperture Z-scan in the plasmonic region of 800 nm reveal that CuS quantum dots are better ultrafast optical limiters compared to CuS nanoparticles.

  16. Ultrafast single-electron transfer in coupled quantum dots driven by a few-cycle chirped pulse

    SciTech Connect (OSTI)

    Yang, Wen-Xing, E-mail: wenxingyang2@126.com [Department of Physics, Southeast University, Nanjing 210096 (China); Institute of Photonics Technologies, National Tsing-Hua University, Hsinchu 300, Taiwan (China); Chen, Ai-Xi [Department of Applied Physics, School of Basic Science, East China Jiaotong University, Nanchang 330013 (China); Bai, Yanfeng [Department of Physics, Southeast University, Nanjing 210096 (China); Lee, Ray-Kuang [Institute of Photonics Technologies, National Tsing-Hua University, Hsinchu 300, Taiwan (China)

    2014-04-14T23:59:59.000Z

    We theoretically study the ultrafast transfer of a single electron between the ground states of a coupled double quantum dot (QD) structure driven by a nonlinear chirped few-cycle laser pulse. A time-dependent Schrödinger equation without the rotating wave approximation is solved numerically. We demonstrate numerically the possibility to have a complete transfer of a single electron by choosing appropriate values of chirped rate parameters and the intensity of the pulse. Even in the presence of the spontaneous emission and dephasing processes of the QD system, high-efficiency coherent transfer of a single electron can be obtained in a wide range of the pulse parameters. Our results illustrate the potential to utilize few-cycle pulses for the excitation in coupled quantum dot systems through the nonlinear chirp parameter control, as well as a guidance in the design of experimental implementation.

  17. Cost effective nanostructured copper substrates prepared with ultrafast laser pulses for explosives detection using surface enhanced Raman scattering

    SciTech Connect (OSTI)

    Hamad, Syed [School of Physics, University of Hyderabad, Prof. C. R. Rao Road, Hyderabad 500046 (India); Podagatlapalli, G. Krishna; Soma, Venugopal Rao, E-mail: svrsp@uohyd.ernet.in, E-mail: soma-venu@yahoo.com [Advanced Center of Research in High Energy Materials (ACRHEM), University of Hyderabad, Prof. C. R. Rao Road, Hyderabad 500046 (India); Mohiddon, Md. Ahamad [Center for Nanotechnology, University of Hyderabad, Prof. C. R. Rao Road, Hyderabad 500046 (India)

    2014-06-30T23:59:59.000Z

    Ultrafast laser pulses induced surface nanostructures were fabricated on a copper (Cu) target through ablation in acetone, dichloromethane, acetonitrile, and chloroform. Surface morphological information accomplished from the field emission scanning electron microscopic data demonstrated the diversities of ablation mechanism in each case. Fabricated Cu substrates were utilized exultantly to investigate the surface plasmon (localized and propagating) mediated enhancements of different analytes using surface enhance Raman scattering (SERS) studies. Multiple utility of these substrates were efficiently demonstrated by collecting the SERS data of Rhodamine 6G molecule and two different secondary explosive molecules such as 5-amino-3-nitro-l,2,4-triazole and trinitrotoluene on different days which were weeks apart. We achieved significant enhancement factors of >10{sup 5} through an easily adoptable cleaning procedure.

  18. Electron-ion relaxation time dependent signal enhancement in ultrafast double-pulse laser-induced breakdown spectroscopy

    SciTech Connect (OSTI)

    Harilal, S. S.; Diwakar, P. K.; Hassanein, A. [Center for Materials Under Extreme Environment, School of Nuclear Engineering, Purdue University, West Lafayette, Indiana 47907 (United States)] [Center for Materials Under Extreme Environment, School of Nuclear Engineering, Purdue University, West Lafayette, Indiana 47907 (United States)

    2013-07-22T23:59:59.000Z

    We investigated the emission properties of collinear double-pulse compared to single-pulse ultrafast laser induced breakdown spectroscopy. Our results showed that the significant signal enhancement noticed in the double pulse scheme is strongly correlated to the characteristic electron-ion relaxation time and hence to the inter-pulse delays. Spectroscopic excitation temperature analysis showed that the improvement in signal enhancement is caused by the delayed pulse efficient reheating of the pre-plume. The signal enhancement is also found to be related to the upper excitation energy of the selected lines, i.e., more enhancement noticed for lines originating from higher excitation energy levels, indicating reheating is the major mechanism behind the signal improvement.

  19. High quality single shot ultrafast MeV electron diffraction from a photocathode radio-frequency gun

    SciTech Connect (OSTI)

    Fu, Feichao; Liu, Shengguang; Zhu, Pengfei; Xiang, Dao, E-mail: dxiang@sjtu.edu.cn; Zhang, Jie, E-mail: jzhang1@sjtu.edu.cn [Key Laboratory for Laser Plasmas (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China); Cao, Jianming [Department of Physics and National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310 (United States)

    2014-08-15T23:59:59.000Z

    A compact ultrafast electron diffractometer, consisting of an s-band 1.6 cell photocathode radio-frequency gun, a multi-function changeable sample chamber, and a sensitive relativistic electron detector, was built at Shanghai Jiao Tong University. High-quality single-shot transmission electron diffraction patterns have been recorded by scattering 2.5?MeV electrons off single crystalline gold and polycrystalline aluminum samples. The high quality diffraction pattern indicates an excellent spatial resolution, with the ratio of the diffraction ring radius over the ring rms width beyond 10. The electron pulse width is estimated to be about 300 fs. The high temporal and spatial resolution may open new opportunities in various areas of sciences.

  20. Vibronic coupling explains the ultrafast carotenoid-to-bacteriochlorophyll energy transfer in natural and artificial light harvesters

    E-Print Network [OSTI]

    Perlík, Václav; Cranston, Laura J; Cogdell, Richard J; Lincoln, Craig N; Savolainen, Janne; Šanda, František; Man?al, Tomáš; Hauer, Jürgen

    2015-01-01T23:59:59.000Z

    The initial energy transfer in photosynthesis occurs between the light-harvesting pigments and on ultrafast timescales. We analyze the carotenoid to bacteriochlorophyll energy transfer in LH2 Marichromatium purpuratum as well as in an artificial light-harvesting dyad system by using transient grating and two-dimensional electronic spectroscopy with 10 fs time resolution. We find that F\\"orster-type models reproduce the experimentally observed 60 fs transfer times, but overestimate coupling constants, which leads to a disagreement with both linear absorption and electronic 2D-spectra. We show that a vibronic model, which treats carotenoid vibrations on both electronic ground and excited state as part of the system's Hamiltonian, reproduces all measured quantities. Importantly, the vibronic model presented here can explain the fast energy transfer rates with only moderate coupling constants, which are in agreement with structure based calculations. Counterintuitively, the vibrational levels on the carotenoid el...

  1. A table-top, repetitive pulsed magnet for nonlinear and ultrafast spectroscopy in high magnetic fields up to 30 T

    SciTech Connect (OSTI)

    Noe, G. Timothy; Lee, Joseph; Woods, Gary L. [Department of Electrical and Computer Engineering, Rice University, Houston, Texas 77005 (United States)] [Department of Electrical and Computer Engineering, Rice University, Houston, Texas 77005 (United States); Nojiri, Hiroyuki [Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan)] [Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); Léotin, Jean [Laboratoire National des Champs Magnétiques Intenses, CNRS-UJF-UPS-INSA, Toulouse (France)] [Laboratoire National des Champs Magnétiques Intenses, CNRS-UJF-UPS-INSA, Toulouse (France); Kono, Junichiro, E-mail: kono@rice.edu [Department of Electrical and Computer Engineering, Rice University, Houston, Texas 77005 (United States) [Department of Electrical and Computer Engineering, Rice University, Houston, Texas 77005 (United States); Department of Physics and Astronomy, Rice University, Houston, Texas 77005, USA and Department of Materials Science and NanoEngineering, Rice University, Houston, Texas 77005 (United States)

    2013-12-15T23:59:59.000Z

    We have developed a mini-coil pulsed magnet system with direct optical access, ideally suited for nonlinear and ultrafast spectroscopy studies of materials in high magnetic fields up to 30 T. The apparatus consists of a small coil in a liquid nitrogen cryostat coupled with a helium flow cryostat to provide sample temperatures down to below 10 K. Direct optical access to the sample is achieved with the use of easily interchangeable windows separated by a short distance of ?135 mm on either side of the coupled cryostats with numerical apertures of 0.20 and 0.03 for measurements employing the Faraday geometry. As a demonstration, we performed time-resolved and time-integrated photoluminescence measurements as well as transmission measurements on InGaAs quantum wells.

  2. Characterization and light-induced dynamics of alkanethiol-capped gold nanoparticles supracrystals by small-angle ultrafast electron diffraction

    E-Print Network [OSTI]

    Mancini, Giulia Fulvia; Pennacchio, Francesco; Reguera, Javier; Stellacci, Francesco; Carbone, Fabrizio

    2015-01-01T23:59:59.000Z

    Metal nanoparticles (NPs) are promising candidates for applications from electronics to medicine. Their metallic core provides some key properties, e.g. magnetization, plasmonic response or conductivity, with the ligand molecules providing others like solubility, assembly or interaction with biomolecules. Even more properties can be engineered when these NPs are used as building blocks to form supracrystals. The formation of these supracrystals depends upon a complex interplay between many forces, some stemming from the core, some from the ligand. At present, there is no known approach to characterize the local order of ligand molecules in such complex supracrystals or their dynamics, with a spatial resolution ranging from the NPs cores and their ligands, to the larger scale domains arrangement. Here, we develop a methodology based on small-angle ultrafast electron diffraction to characterize different two-dimensional supracrystals of alkanethiol-coated gold nanoparticles with femtosecond time, sub-nanometer ...

  3. Ultrafast transmission electron microscopy on dynamic process of a CDW transition in 1T-TaSe2

    E-Print Network [OSTI]

    Sun, Shuaishuai; Li, Zhongwen; Cao, Gaolong; Liu, Y; Lu, W J; Sun, Y P; Tian, Huanfang; HuaixinYang,; Li, Jianqi

    2015-01-01T23:59:59.000Z

    Four-dimensional ultrafast transmission electron microscopy (4D-UTEM) measurements reveal a rich variety of structural dynamic phenomena at a phase transition in the charge-density-wave (CDW) 1T-TaSe2. Through the photoexcitation, remarkable changes on both the CDW intensity and orientation are clearly observed associated with the transformation from a commensurate (C) into an incommensurate (IC) phase in a time-scale of about 3 ps. Moreover, the transient states show up a notable "structurally isosbestic point" at a wave vector of qiso where the C and IC phases yield their diffracting efficiencies in an equally ratio. This fact demonstrates that the crystal planes parallel to qiso adopts visibly common structural features in these two CDW phases. The second-order characters observed in this nonequilibrium phase transition have been also analyzed based on the time-resolved structural data.

  4. Theoretical Physics

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

    a hierarchy problem? Are there new physical principles at the TeV scale? Is the Higgs boson a fundamental particle or composite, like a pion? What is the final state of...

  5. Physical Scientist

    Broader source: Energy.gov [DOE]

    The Office of Science is the single largest supporter of basic research in the physical sciences in the United States, providing more than 40 percent of total funding for this vital area of...

  6. System and method for ultrafast optical signal detecting via a synchronously coupled anamorphic light pulse encoded laterally

    DOE Patents [OSTI]

    Heebner, John E. (Livermore, CA)

    2010-08-03T23:59:59.000Z

    In one general embodiment, a method for ultrafast optical signal detecting is provided. In operation, a first optical input signal is propagated through a first wave guiding layer of a waveguide. Additionally, a second optical input signal is propagated through a second wave guiding layer of the waveguide. Furthermore, an optical control signal is applied to a top of the waveguide, the optical control signal being oriented diagonally relative to the top of the waveguide such that the application is used to influence at least a portion of the first optical input signal propagating through the first wave guiding layer of the waveguide. In addition, the first and the second optical input signals output from the waveguide are combined. Further, the combined optical signals output from the waveguide are detected. In another general embodiment, a system for ultrafast optical signal recording is provided comprising a waveguide including a plurality of wave guiding layers, an optical control source positioned to propagate an optical control signal towards the waveguide in a diagonal orientation relative to a top of the waveguide, at least one optical input source positioned to input an optical input signal into at least a first and a second wave guiding layer of the waveguide, and a detector for detecting at least one interference pattern output from the waveguide, where at least one of the interference patterns results from a combination of the optical input signals input into the first and the second wave guiding layer. Furthermore, propagation of the optical control signal is used to influence at least a portion of the optical input signal propagating through the first wave guiding layer of the waveguide.

  7. A physical sciences network characterization of non-tumorigenic and metastatic cells

    E-Print Network [OSTI]

    Jacks, Tyler E.

    To investigate the transition from non-cancerous to metastatic from a physical sciences perspective, the Physical Sciences–Oncology Centers (PS-OC) Network performed molecular and biophysical comparative studies of the ...

  8. Progress at LAMPF (Los Alamos Meson Physics Facility), January--December 1989

    SciTech Connect (OSTI)

    Poelakker, K. (ed.)

    1990-12-01T23:59:59.000Z

    This report contains brief papers on research conducted at the lampf facility in the following areas: nuclear and particle physics; astrophysics; atomic and molecular physics; materials science; nuclear chemistry; radiation effects and radioisotope production.

  9. Epsilon-Near-Zero Al-Doped ZnO for Ultrafast Switching at Telecom Wavelengths: Outpacing the Traditional Amplitude-Bandwidth Trade-Off

    E-Print Network [OSTI]

    Kinsey, N; Kim, J; Ferrera, M; Shalaev, V M; Boltasseva, A

    2015-01-01T23:59:59.000Z

    Transparent conducting oxides have recently gained great attention as CMOS-compatible materials for applications in nanophotonics due to their low optical loss, metal-like behavior, versatile/tailorable optical properties, and established fabrication procedures. In particular, aluminum doped zinc oxide (AZO) is very attractive because its dielectric permittivity can be engineered over a broad range in the near infrared and infrared. However, despite all these beneficial features, the slow (> 100 ps) electron-hole recombination time typical of these compounds still represents a fundamental limitation impeding ultrafast optical modulation. Here we report the first epsilon-near-zero AZO thin films which simultaneously exhibit ultra-fast carrier dynamics (excitation and recombination time below 1 ps) and an outstanding reflectance modulation up to 40% for very low pump fluence levels (< 4 mJ/cm2) at the telecom wavelength of 1.3 {\\mu}m. The unique properties of the demonstrated AZO thin films are the result of...

  10. Repetition of the shape of the ultrafast self-modulation of the optical absorption spectrum upon varying the energy of pulse of GaAs pumping

    SciTech Connect (OSTI)

    Ageeva, N. N.; Bronevoi, I. L., E-mail: bil@cplire.ru; Zabegaev, D. N.; Krivonosov, A. N. [Russian Academy of Sciences, Kotel'nikov Institute of Radio Engineering and Electronics (Russian Federation)

    2010-10-15T23:59:59.000Z

    Ultrafast self-modulation of the fundamental optical absorption emerges during intense picosecond optical pumping of GaAs and, according to the main assumption, reflects self-oscillations of depletion of electron populations in the conduction band. In this study, the quantitatively confirmed explanation of previously experimentally found cyclic repetition of the form of ultrafast self-modulation of the absorption spectrum upon varying the energy of the pumping pulse and fixed delay between pumping and probing (the measurement of absorption) is given. Repetition of the shape is explained by varying the phase of self-oscillations of the optical absorption. The explanation is based on the previously found experimentally dependence of the frequency of self-oscillations of absorption on the pumping energy. Therefore, this is also a new confirmation of the mentioned dependence (which satisfactorily coincides with a similar calculated dependence of the frequency of self-oscillations of depletion of populations).

  11. Synthesis, Characterization, and Ultrafast Dynamics of Metal, Metal Oxide, and Semiconductor Nanomaterials

    E-Print Network [OSTI]

    Wheeler, Damon Andreas

    2013-01-01T23:59:59.000Z

    Solar Absorption for Photocatalysis with Black Hydrogenatedof physical Chemistry C Photocatalysis of Ag-Loaded TiO 2Lu, G. ; Yates, J. T. , Photocatalysis on TiO2 Surfaces:

  12. REVIEW OF PARTICLE PHYSICS

    E-Print Network [OSTI]

    Beringer, Juerg

    2013-01-01T23:59:59.000Z

    387 Colliders, accelerator physics of Coverage Color octet50, 974 Accelerator physics offor non-accelerator physics . . . . . . . . . 368 Number

  13. Center for Beam Physics

    E-Print Network [OSTI]

    Chattopadhyay, S.

    2010-01-01T23:59:59.000Z

    Symposium on Accelerator Physics (1994). "The Development ofcolliders", Accelerator Physics at the Superconducting Superaccelerators, accelerator physics, linear colliders, heavy

  14. Ultrafast Photooxidation of Mn(II)-Terpyridine Complexes Covalently Attached to TiO2 Nanoparticles

    E-Print Network [OSTI]

    -energy conversion by dye-sensitized solar cells,1,2 photocatalysis,3-6 and molecular electronics.7,8 Most previous-cost, high-efficiency solar cell based on Ru-dye sensitization of colloidal TiO2 films.1 Presently, the most studies have been focused on TiO2 nanoparticles sensitized with Ru dyes,9,10 although IET in other

  15. Planetary Physics

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742EnergyOnItemResearch > TheNuclear AstrophysicsPayroll,Physics Physics An error

  16. Plasma Physics

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742EnergyOnItemResearch > TheNuclear AstrophysicsPayroll,Physics Physics An

  17. Physics 15030401 Special Topics in Modern Physics

    E-Print Network [OSTI]

    Johnson, Randy

    Physics 15­030­401 Special Topics in Modern Physics Probability and Statistics for Physics Randy Johnson Summer, '96 Text Bevington and Robinson, Data Reduction and Error Analysis for the Physical Physics. Eardie, Drijard, James, Roos, and Sadoulet, Statistical Methods in Experimental Physics. Roe

  18. Physical Protection

    Broader source: Directives, Delegations, and Requirements [Office of Management (MA)]

    2009-07-23T23:59:59.000Z

    This Manual establishes requirements for the physical protection of interests under the U.S. Department of Energys (DOEs) purview ranging from facilities, buildings, Government property, and employees to national security interests such as classified information, special nuclear material (SNM), and nuclear weapons. Cancels Section A of DOE M 470.4-2 Chg 1. Canceled by DOE O 473.3.

  19. DEPARTAMENTO DE BIOMEDICINA MOLECULAR

    E-Print Network [OSTI]

    . Estudio celular y mo- lecular de malaria maternal. rohernan@mail.cinvestav.mx ÍndiceÍndiceÍndice #12 (1994) Cinvestav. Temas de investigación: Estudio molecular y celular de las proteínas involucradas en el patogénesis de la amibiasis y caracterización molecular de la motilidad celular en Entamoeba

  20. Coherent THz electromagnetic radiation emission as a shock wave diagnostic and probe of ultrafast phase transformations

    SciTech Connect (OSTI)

    Reed, E J; Armstrong, M R; Kim, K Y; Glownia, J H; Howard, M; Piner, E; Roberts, J

    2009-06-30T23:59:59.000Z

    We present the first experimental observations of terahertz frequency radiation emitted when a terahertz frequency acoustic wave propagates past an interface between materials of differing piezoelectric coefficients. We show that this fundamentally new phenomenon can be used to probe structural properties of thin films. Then, we present molecular dynamics simulations showing that detectable THz frequency radiation can be emitted when a wurtzite structure crystal transforms to a rocksalt structure under shock compression on picosecond timescales. We show that information about the kinetics of the transformation is contained in the time-dependence of the THz field.

  1. Computational Physics on Graphics Processing Units

    E-Print Network [OSTI]

    Harju, Ari; Federici-Canova, Filippo; Hakala, Samuli; Rantalaiho, Teemu

    2012-01-01T23:59:59.000Z

    The use of graphics processing units for scientific computations is an emerging strategy that can significantly speed up various different algorithms. In this review, we discuss advances made in the field of computational physics, focusing on classical molecular dynamics, and on quantum simulations for electronic structure calculations using the density functional theory, wave function techniques, and quantum field theory.

  2. Computational Physics on Graphics Processing Units

    E-Print Network [OSTI]

    Ari Harju; Topi Siro; Filippo Federici-Canova; Samuli Hakala; Teemu Rantalaiho

    2013-03-06T23:59:59.000Z

    The use of graphics processing units for scientific computations is an emerging strategy that can significantly speed up various different algorithms. In this review, we discuss advances made in the field of computational physics, focusing on classical molecular dynamics, and on quantum simulations for electronic structure calculations using the density functional theory, wave function techniques, and quantum field theory.

  3. Physical Protection

    Broader source: Directives, Delegations, and Requirements [Office of Management (MA)]

    2005-08-26T23:59:59.000Z

    This Manual establishes requirements for the physical protection of safeguards and security interests. Copies of Section B, Safeguards and Security Alarm Management System, which contains Unclassified Controlled Nuclear Information, and Appendix 1, Security Badge Specifications, which contains Official Use Only information, are only available, by request, from the program manager, Protection Program Operations, 301-903-6209. Chg 1, dated 3/7/06. Cancels: DOE M 473.1-1 and DOE M 471.2-1B

  4. Physical Protection

    Broader source: Directives, Delegations, and Requirements [Office of Management (MA)]

    2005-08-26T23:59:59.000Z

    Establishes requirements for the physical protection of safeguards and security interests. Copies of Section B, Safeguards and Security Alarm Management System, which contains Unclassified Controlled Nuclear Information, and Appendix 1, Security Badge Specifications, which contains Official Use Only information, are only available, by request, from the program manager, Protection Program Operations, 301-903-6209. Cancels: DOE M 473.1-1 and DOE M 471.2-1B.

  5. Molecular heat pump

    E-Print Network [OSTI]

    Dvira Segal; Abraham Nitzan

    2005-10-11T23:59:59.000Z

    We propose a novel molecular device that pumps heat against a thermal gradient. The system consists of a molecular element connecting two thermal reservoirs that are characterized by different spectral properties. The pumping action is achieved by applying an external force that periodically modulates molecular levels. This modulation affects periodic oscillations of the internal temperature of the molecule and the strength of its coupling to each reservoir resulting in a net heat flow in the desired direction. The heat flow is examined in the slow and fast modulation limits and for different modulation waveforms, thus making it possible to optimize the device performance.

  6. Physics and Astronomy Radiation Safety Physics Concentration

    E-Print Network [OSTI]

    Thaxton, Christopher S.

    Physics and Astronomy Radiation Safety Physics Concentration Strongly recommended courses Credits Environucleonics Lab 1 PHY 3211 Modern Physics II 3 PHY 3230 Thermal Physics 3 PHY 4330 Digital Electronics 3 PHY 4820 Medical Physics 3 CHE 1101 Intro. Chemistry I 3 CHE 1110 Intro. Chemistry I Lab 1 CHE 1102 Intro

  7. Physics and Astronomy Engineering/Physics Concentration

    E-Print Network [OSTI]

    Thaxton, Christopher S.

    Physics and Astronomy Engineering/Physics Concentration Strongly recommended courses Credits Term Electromagnetic Fields & Waves 3 PHY 3230 Thermal Physics 3 PHY 4020 Computational Methods in Physics.) taken Grade PHY 4620 Optics 4 PHY 3211 Modern Physics II 3 PHY 4730 Analog Circuits 3 PHY 4640 Quantum

  8. 314 Department of Physics Department of Physics

    E-Print Network [OSTI]

    Nagle, John F.

    314 Department of Physics Department of Physics Physics, one of the basic sciences, has its origin led to the detailed understanding of a remarkable variety of physical phenomena. Our knowledge now comprehension of the physical world forms an impressive part of the intellectual and cultural heritage of our

  9. Ultrafast crystalline-to-amorphous phase transition in Ge{sub 2}Sb{sub 2}Te{sub 5} chalcogenide alloy thin film using single-shot imaging spectroscopy

    SciTech Connect (OSTI)

    Takeda, Jun, E-mail: jun@ynu.ac.jp; Oba, Wataru; Minami, Yasuo; Katayama, Ikufumi [Department of Physics, Graduate School of Engineering, Yokohama National University, Yokohama 240-8501 (Japan); Saiki, Toshiharu [Graduate School of Science and Technology, Keio University, Yokohama 223-8522 (Japan)

    2014-06-30T23:59:59.000Z

    We have observed an irreversible ultrafast crystalline-to-amorphous phase transition in Ge{sub 2}Sb{sub 2}Te{sub 5} chalcogenide alloy thin film using broadband single-shot imaging spectroscopy. The absorbance change that accompanied the ultrafast amorphization was measured via single-shot detection even for laser fluences above the critical value, where a permanent amorphized mark was formed. The observed rise time to reach the amorphization was found to be ?130–200 fs, which was in good agreement with the half period of the A{sub 1} phonon frequency in the octahedral GeTe{sub 6} structure. This result strongly suggests that the ultrafast amorphization can be attributed to the rearrangement of Ge atoms from an octahedral structure to a tetrahedral structure. Finally, based on the dependence of the absorbance change on the laser fluence, the stability of the photoinduced amorphous phase is discussed.

  10. Laser Control of Dissipative Two-Exciton Dynamics in Molecular Aggregates

    E-Print Network [OSTI]

    Yun-an Yan; Oliver Kühn

    2012-07-09T23:59:59.000Z

    There are two types of two-photon transitions in molecular aggregates, that is, non-local excitations of two monomers and local double excitations to some higher excited intra-monomer electronic state. As a consequence of the inter-monomer Coulomb interaction these different excitation states are coupled to each other. Higher excited intra-monomer states are rather short-lived due to efficient internal conversion of electronic into vibrational energy. Combining both processes leads to the annihilation of an electronic excitation state, which is a major loss channel for establishing high excitation densities in molecular aggregates. Applying theoretical pulse optimization techniques to a Frenkel exciton model it is shown that the dynamics of two-exciton states in linear aggregates (dimer to tetramer) can be influenced by ultrafast shaped laser pulses. In particular, it is studied to what extent the decay of the two-exciton population by inter-band transitions can be transiently suppressed. Intra-band dynamics is described by a dissipative hierarchy equation approach, which takes into account strong exciton-vibrational coupling in the non-Markovian regime.

  11. In-situ weak-beam and polarization control of multidimensional laser sidebands for ultrafast optical switching

    SciTech Connect (OSTI)

    Liu, Weimin; Wang, Liang; Fang, Chong, E-mail: Chong.Fang@oregonstate.edu [Department of Chemistry, Oregon State University, Corvallis, Oregon 97331 (United States)

    2014-03-17T23:59:59.000Z

    All-optical switching has myriad applications in optoelectronics, optical communications, and quantum information technology. To achieve ultrafast optical switching in a compact yet versatile setup, we demonstrate distinct sets of two-dimensional (2D) broadband up-converted multicolor arrays (BUMAs) in a thin type-I ?-barium-borate crystal with two noncollinear near-IR femtosecond pulses at various phase-matching conditions. The unique interaction mechanism is revealed as quadratic spatial solitons (QSSs)-coupled cascaded four-wave mixing (CFWM), corroborated by numerical calculations of the governing phase-matching conditions. Broad and continuous spectral-spatial tunability of the 2D BUMAs are achieved by varying the time delay between the two incident pulses that undergo CFWM interaction, rooted in the chirped nature of the weak white light and the QSSs generation of the intense fundamental beam. The control of 2D BUMAs is accomplished via seeding a weak second-harmonic pulse in situ to suppress the 2D arrays with polarization dependence on the femtosecond timescale that matches the control pulse duration of ?35 fs. A potential application is proposed on femtosecond all-optical switching in an integrated wavelength-time division multiplexing device.

  12. Ultrafast Large Area Micropattern Generation in Non-absorbing Polymer Thin-Films by Pulsed Laser Diffraction

    E-Print Network [OSTI]

    Ankur Verma; Ashutosh Sharma; Giridhar U. Kulkarni

    2011-01-27T23:59:59.000Z

    We report an ultrafast, parallel and beyond-the-master micro-patterning technique for ultrathin (30 nm-400 nm) non-absorbing polymer films by diffraction of a laser light through a two dimensional periodic aperture. The redistribution of laser energy absorbed by the substrate causes self-organization of polymer thin-film in the form of wrinkle like surface relief structures caused by localized melting and freezing of the thin-film. Unlike the conventional laser ablation and laser writing processes, low laser fluence is employed to only passively swell the polymer as a pre-ablative process without the loss of material, and without absorption/reaction with the incident radiation. Self-organization in the thin polymer film aided by the diffraction pattern produces micro-structures made up of thin raised lines. These regular microstructures have far more complex morphologies than the mask geometry and very narrow line widths that can be an order of magnitude smaller than the openings in the mask. The microstructure morphology is easily modulated by changing the film thickness, aperture size and geometry and by changing the diffraction pattern, e.g., by changing the aperture-substrate distance.

  13. Optimization of chemical compositions in low-carbon Al-killed enamel steel produced by ultra-fast continuous annealing

    SciTech Connect (OSTI)

    Dong, Futao, E-mail: dongft@sina.com [The State Key Laboratory of Rolling and Automation, Northeastern University, Shenyang 110819 (China); Du, Linxiu; Liu, Xianghua [The State Key Laboratory of Rolling and Automation, Northeastern University, Shenyang 110819 (China); Xue, Fei [College of Electrical Engineering, Hebei United University, Tangshan 063000 (China)

    2013-10-15T23:59:59.000Z

    The influence of Mn,S and B contents on microstructural characteristics, mechanical properties and hydrogen trapping ability of low-carbon Al-killed enamel steel was investigated. The materials were produced and processed in a laboratory and the ultra-fast continuous annealing processing was performed using a continuous annealing simulator. It was found that increasing Mn,S contents in steel can improve its hydrogen trapping ability which is attributed by refined ferrite grains, more dispersed cementite and added MnS inclusions. Nevertheless, it deteriorates mechanical properties of steel sheet. Addition of trace boron results in both good mechanical properties and significantly improved hydrogen trapping ability. The boron combined with nitrogen segregating at grain boundaries, cementite and MnS inclusions, provides higher amount of attractive hydrogen trapping sites and raises the activation energy for hydrogen desorption from them. - Highlights: • We study microstructures and properties in low-carbon Al-killed enamel steel. • Hydrogen diffusion coefficients are measured to reflect fish-scale resistance. • Manganese improves hydrogen trapping ability but decrease deep-drawing ability. • Boron improves both hydrogen trapping ability and deep-drawing ability. • Both excellent mechanical properties and fish-scale resistance can be matched.

  14. A simple electron time-of-flight spectrometer for ultrafast vacuum ultraviolet photoelectron spectroscopy of liquid solutions

    SciTech Connect (OSTI)

    Arrell, C. A., E-mail: christopher.arrell@epfl.ch; Ojeda, J.; Mourik, F. van; Chergui, M. [Laboratory of Ultrafast Spectroscopy, ISIC, Station 6, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne (Switzerland); Sabbar, M.; Gallmann, L.; Keller, U. [Physics Department, ETH Zurich, 8093 Zurich (Switzerland); Okell, W. A.; Witting, T.; Siegel, T.; Diveki, Z.; Hutchinson, S.; Tisch, J. W.G.; Marangos, J. P. [Department of Physics, The Blackett Laboratory, Imperial College, London SW7 2AZ (United Kingdom); Chapman, R. T.; Cacho, C.; Rodrigues, N.; Turcu, I. C.E.; Springate, E. [Central Laser Facility, STFC Rutherford Appleton Laboratory, Oxon OX11 0QX (United Kingdom)

    2014-10-15T23:59:59.000Z

    We present a simple electron time of flight spectrometer for time resolved photoelectron spectroscopy of liquid samples using a vacuum ultraviolet (VUV) source produced by high-harmonic generation. The field free spectrometer coupled with the time-preserving monochromator for the VUV at the Artemis facility of the Rutherford Appleton Laboratory achieves an energy resolution of 0.65 eV at 40 eV with a sub 100 fs temporal resolution. A key feature of the design is a differentially pumped drift tube allowing a microliquid jet to be aligned and started at ambient atmosphere while preserving a pressure of 10{sup ?1} mbar at the micro channel plate detector. The pumping requirements for photoelectron (PE) spectroscopy in vacuum are presented, while the instrument performance is demonstrated with PE spectra of salt solutions in water. The capability of the instrument for time resolved measurements is demonstrated by observing the ultrafast (50 fs) vibrational excitation of water leading to temporary proton transfer.

  15. NuSTAR Reveals Relativistic Reflection But No Ultra-Fast Outflow In The Quasar PG 1211+143

    E-Print Network [OSTI]

    Zoghbi, A; Walton, D J; Harrison, F A; Fabian, A C; Reynolds, C S; Boggs, S E; Christensen, F E; Craig, W; Hailey, C J; Stern, D; Zhang, W W

    2015-01-01T23:59:59.000Z

    We report on four epochs of observations of the quasar PG 1211+143 using NuSTAR. The net exposure time is 300 ks. Prior work on this source found suggestive evidence of an 'ultra-fast outflow' (or, UFO) in the Fe K band, with a velocity of approximately 0.1c. The putative flow would carry away a high mass flux and kinetic power, with broad implications for feedback and black hole-galaxy co-evolution. NuSTAR detects PG 1211+143 out to 30 keV, meaning that the continuum is well-defined both through and above the Fe K band. A characteristic relativistic disk reflection spectrum is clearly revealed, via a broad Fe K emission line and Compton back-scattering curvature. The data offer only weak constraints on the spin of the black hole. A careful search for UFO's show no significant absorption feature above 90% confidence. The limits are particularly tight when relativistic reflection is included. We discuss the statistics and the implications of these results in terms of connections between accretion onto quasars,...

  16. January 2010 Physics 3300

    E-Print Network [OSTI]

    deYoung, Brad

    1 January 2010 Physics 3300 Introduction to Physical Oceanography Instructor: Brad de Young Physics and Physical Oceanography Memorial University, bdeyoung@mun.ca Room C-3000 737-8738 Physics 3300 Introduction to Physical Oceanography deals with the physics of the processes in the ocean, providing an integrating view

  17. Hadron physics

    SciTech Connect (OSTI)

    Bunce, G.

    1984-05-30T23:59:59.000Z

    Is all hadronic physics ultimately describable by QCD. Certainly, many disparate phenomena can be understood within the QCD framework. Also certainly, there are important questions which are open, both theoretically (little guidance, as yet) and experimentally, regarding confinement. Are there dibaryons, baryonium, glueballs. In addition, there are experimental results which at present do not have an explanation. This talk, after a short section on QCD successes and difficulties, will emphasize two experimental topics which have recent results - glueball spectroscopy and exclusive reactions at large momentum transfer. Both are experimentally accessible in the AGS/LAMPF II/AGS II/TRIUMF II/SIN II energy domain.

  18. Physical Sciences

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of Science (SC)IntegratedSpeeding accessPeptoid NanosheetsStudyingFebruary PhotonsPhysical Sciences

  19. Asymptotic Analysis of Cooperative Molecular Motor System

    E-Print Network [OSTI]

    Durrett, Richard

    Mesoscale Model for Collections of Molecular Motors Stochastic Asymptotic Techniques #12;Molecular Motors

  20. Ab initio studies of ultrafast x-ray scattering of the photodissociation of iodine

    SciTech Connect (OSTI)

    Debnarova, Andrea; Techert, Simone [Max Planck Institute for Biophysical Chemistry, 37077 Goettingen, Am Fassberg 11 (Germany); Schmatz, Stefan [Institut fuer Physikalische Chemie, Universitaet Goettingen, 37077 Goettingen, Tammannstr. 6 (Germany)

    2010-09-28T23:59:59.000Z

    We computationally examine various aspects of the reaction dynamics of the photodissociation and recombination of molecular iodine. We use our recently proposed formalism to calculate time-dependent x-ray scattering signal changes from first principles. Different aspects of the dynamics of this prototypical reaction are studied, such as coherent and noncoherent processes, features of structural relaxation that are periodic in time versus nonperiodic dissociative processes, as well as small electron density changes caused by electronic excitation, all with respect to x-ray scattering. We can demonstrate that wide-angle x-ray scattering offers a possibility to study the changes in electron densities in nonperiodic systems, which render it a suitable technique for the investigation of chemical reactions from a structural dynamics point of view.

  1. Development of Nanofluidic Cells for Ultrafast X-ray Studies of Water

    SciTech Connect (OSTI)

    Irizarry, Melvin E.; /Puerto Rico U., Mayaguez /SLAC

    2006-08-23T23:59:59.000Z

    In order to study the molecular structure and dynamics of liquid water with soft x-ray probes, samples with nanoscale dimensions are needed. This paper describes a simple method for preparing nanofluidic water cells. The idea is to confine a thin layer of water between two silicon nitride windows. The windows are 1 mm x 1 mm and 0.5 mm x 0.5 mm in size and have a thickness of 150 nm. The thickness of the water layer was measured experimentally by probing the infrared spectrum of water in the cells with a Fourier Transform InfraRed (FTIR) apparatus and from soft x-ray static measurements at the Advanced Light Source (ALS) at Lawrence Berkeley National Laboratory. Water layers ranging from 10 nm to more than 2 {micro}m were observed. Evidence for changes in the water structure compared to bulk water is observed in the ultrathin cells.

  2. Review of Particle Physics

    E-Print Network [OSTI]

    Nakamura, Kenzo

    2010-01-01T23:59:59.000Z

    Conference on Neutrino Physics and Astrophysics - “Neutrino’Kim, Fundamentals of Neutrino Physics and Astrophysics (Fermi”, CLII Course “Neutrino Physics”, 23 July-2 August

  3. REVIEW OF PARTICLE PHYSICS

    E-Print Network [OSTI]

    Beringer, Juerg

    2013-01-01T23:59:59.000Z

    Conference on Neutrino Physics and Astrophysics - “Neutrino’Kim, Fundamentals of Neutrino Physics and Astrophysics (Fermi”, CLII Course “Neutrino Physics”, 23 July-2 August

  4. Review of Particle Physics

    E-Print Network [OSTI]

    Nakamura, Kenzo

    2010-01-01T23:59:59.000Z

    for non-accelerator physics . . . . . . . . . 328 ParticleColliders, accelerator physics of Coupling between matterdetectors for non-accelerator physics (Figure 29.5) . . .

  5. High-stability time-domain balanced homodyne detector for ultrafast optical pulse applications

    E-Print Network [OSTI]

    Merlin Cooper; Christoph Söller; Brian J. Smith

    2013-03-25T23:59:59.000Z

    Low-noise, efficient, phase-sensitive time-domain optical detection is essential for foundational tests of quantum physics based on optical quantum states and the realization of numerous applications ranging from quantum key distribution to coherent classical telecommunications. Stability, bandwidth, efficiency, and signal-to-noise ratio are crucial performance parameters for effective detector operation. Here we present a high-bandwidth, low-noise, ultra-stable time-domain coherent measurement scheme based on balanced homodyne detection ideally suited to characterization of quantum and classical light fields in well-defined ultrashort optical pulse modes.

  6. Complete Photoionization Experiments via Ultrafast Coherent Control with Polarization Multiplexing II: Numerics & Analysis Methodologies

    E-Print Network [OSTI]

    Hockett, P; Lux, C; Baumert, T

    2015-01-01T23:59:59.000Z

    The feasibility of complete photoionization experiments, in which the full set of photoionization matrix elements are determined, using multiphoton ionization schemes with polarization-shaped pulses has recently been demonstrated [Hockett et. al., Phys. Rev. Lett. 112, 223001 (2014)]. Here we extend on our previous work to discuss further details of the numerics and analysis methodology utilised, and compare the results directly to new tomographic photoelectron measurements, which provide a more sensitive test of the validity of the results. In so doing we discuss in detail the physics of the photoionziation process, and suggest various avenues and prospects for this coherent multiplexing methodology.

  7. Molecular Physics Vol. 109, No. 22, 20 November 2011, 26932708

    E-Print Network [OSTI]

    spectrometry (PIFS) using the 10 m normal incidence monochromator at the synchrotron BESSY II. Using the FT­Fano resonances, were studied up to v ¼ 18. The 10 m normal incidence beamline setup at BESSY II was used

  8. Physical Mapping of Chromosomes: A Combinatorial Problem in Molecular Biology

    E-Print Network [OSTI]

    Alizadeh, Farid

    of nucleotides from the set fA; T ; C;Gg. The nucleotides A and T are complementary to each other, as are the nucleotides C and G. Each nucleotide on one strand is bound to a complementary nucleotide on the other strand will cleave a DNA molecule at every site where a certain short sequence of nucleotides occurs. A separation

  9. Physics 6321 Coastal oceanography

    E-Print Network [OSTI]

    deYoung, Brad

    Physics 6321 Coastal oceanography · Instructor: Dr. Iakov Afanassiev · Office: Physics C-4065 · email: yakov@physics.mun.ca · Course Times: TBD Room TBD · Office Hours: unlimited · Web Page: http://www.physics

  10. Ultrafast all-optical switching and error-free 10 Gbit/s wavelength conversion in hybrid InP-silicon on insulator nanocavities using surface quantum wells

    SciTech Connect (OSTI)

    Bazin, Alexandre; Monnier, Paul; Beaudoin, Grégoire; Sagnes, Isabelle; Raj, Rama [Laboratoire de Photonique et de Nanostructures (CNRS UPR20), Route de Nozay, Marcoussis 91460 (France)] [Laboratoire de Photonique et de Nanostructures (CNRS UPR20), Route de Nozay, Marcoussis 91460 (France); Lenglé, Kevin; Gay, Mathilde; Bramerie, Laurent [Université Européenne de Bretagne (UEB), 5 Boulevard Laënnec, 35000 Rennes (France) [Université Européenne de Bretagne (UEB), 5 Boulevard Laënnec, 35000 Rennes (France); CNRS-Foton Laboratory (UMR 6082), Enssat, BP 80518, 22305 Lannion Cedex (France); Braive, Rémy; Raineri, Fabrice, E-mail: fabrice.raineri@lpn.cnrs.fr [Laboratoire de Photonique et de Nanostructures (CNRS UPR20), Route de Nozay, Marcoussis 91460 (France) [Laboratoire de Photonique et de Nanostructures (CNRS UPR20), Route de Nozay, Marcoussis 91460 (France); Université Paris Diderot, Sorbonne Paris Cité, 75207 Paris Cedex 13 (France)

    2014-01-06T23:59:59.000Z

    Ultrafast switching with low energies is demonstrated using InP photonic crystal nanocavities embedding InGaAs surface quantum wells heterogeneously integrated to a silicon on insulator waveguide circuitry. Thanks to the engineered enhancement of surface non radiative recombination of carriers, switching time is obtained to be as fast as 10?ps. These hybrid nanostructures are shown to be capable of achieving systems level performance by demonstrating error free wavelength conversion at 10 Gbit/s with 6 mW switching powers.

  11. Self-doped molecular composite battery electrolytes

    DOE Patents [OSTI]

    Harrup, Mason K.; Wertsching, Alan K.; Stewart, Frederick F.

    2003-04-08T23:59:59.000Z

    This invention is in solid polymer-based electrolytes for battery applications. It uses molecular composite technology, coupled with unique preparation techniques to render a self-doped, stabilized electrolyte material suitable for inclusion in both primary and secondary batteries. In particular, a salt is incorporated in a nano-composite material formed by the in situ catalyzed condensation of a ceramic precursor in the presence of a solvated polymer material, utilizing a condensation agent comprised of at least one cation amenable to SPE applications. As such, the counterion in the condensation agent used in the formation of the molecular composite is already present as the electrolyte matrix develops. This procedure effectively decouples the cation loading levels required for maximum ionic conductivity from electrolyte physical properties associated with condensation agent loading levels by utilizing the inverse relationship discovered between condensation agent loading and the time domain of the aging step.

  12. Color Imaging Arithmetic: Physics Math > Physics + Math

    E-Print Network [OSTI]

    Sharma, Gaurav

    Color Imaging Arithmetic: Physics Math > Physics + Math Gaurav Sharma University of Rochester inter- action commonly form the physical interface by which we connect to the digital cyber-world. Because these devices bridge the physical and the electronic worlds, elegant and effective solutions

  13. Physics and Astronomy Chemical Physics Concentration

    E-Print Network [OSTI]

    Thaxton, Christopher S.

    Physics and Astronomy Chemical Physics Concentration Strongly recommended courses Credits Term Dept Fields & Waves 3 PHY 3230 Thermal Physics 3 PHY 4640 Quantum Mechanics 3 PHY 4020 Computational Methods in Physics & Engineering 3 PHY 4330 Digital Electronics 3 CHE 1101 Intro. Chemistry I 3 CHE 1110 Intro

  14. People's Physics Book The People's Physics Book

    E-Print Network [OSTI]

    California at Santa Cruz, University of

    People's Physics Book The People's Physics Book Authors James H. Dann, Ph.D. James J. Dann. All rights reserved. Textbook Website http://scipp.ucsc.edu/outreach/index2.html #12;People's Physics, and many of the problems. We also thank our fellow physics teachers at both schools for their immense help

  15. People's Physics Book The People's Physics Book

    E-Print Network [OSTI]

    California at Santa Cruz, University of

    #12;People's Physics Book The People's Physics Book Authors James H. Dann, Ph.D. James J. Dann. All rights reserved. Textbook Website http://scipp.ucsc.edu/outreach/index2.html #12;People's Physics, and many of the problems. We also thank our fellow physics teachers at both schools for their immense help

  16. Theoretical Determination of the Dissociation Energy of Molecular Hydrogen

    E-Print Network [OSTI]

    Pachucki, Krzysztof

    Physics, University of Warsaw, Hoza 69, 00-681 Warsaw, Poland Abstract The dissociation energyTheoretical Determination of the Dissociation Energy of Molecular Hydrogen Konrad Piszczatowski of Chemistry, University of Warsaw, Pasteura 1, 02-093, Warsaw, Poland, Center for Theoretical

  17. Fundamentals of Plasma Physics

    E-Print Network [OSTI]

    Callen, James D.

    of students (from physics, engineering physics, elec- trical engineering, nuclear engineering and other un;PREFACE Plasma physics is a relatively new branch of physics that became a mature science over the last). Thus, plasma physics has developed in large part as a branch of applied or engineering physics

  18. Ultrafast probing of the x-ray-induced lattice and electron dynamics in graphite at atomic-resolution

    SciTech Connect (OSTI)

    Hau-Riege, S

    2010-10-07T23:59:59.000Z

    We used LCLS pulses to excite thin-film and bulk graphite with various different microstructures, and probed the ultrafast ion and electron dynamics through Bragg and x-ray Thomson scattering (XRTS). We pioneered XRTS at LCLS, making this technique viable for other users. We demonstrated for the first time that the LCLS can be used to characterize warm-dense-matter through Bragg and x-ray Thomson scattering. The warm-dense-matter conditions were created using the LCLS beam. Representative examples of the results are shown in the Figure above. In our experiment, we utilized simultaneously both Bragg and two Thomson spectrometers. The Bragg measurements as a function of x-ray fluence and pulse length allows us to characterize the onset of atomic motion at 2 keV with the highest resolution to date. The Bragg detector was positioned in back-reflection, providing us access to scattering data with large scattering vectors (nearly 4{pi}/{lambda}). We found a clear difference between the atomic dynamics for 70 and 300 fs pulses, and we are currently in the process of comparing these results to our models. The outcome of this comparison will have important consequences for ultrafast diffractive imaging, for which it is still not clear if atomic resolution can truly be achieved. The backward x-ray Thomson scattering data suggests that the average graphite temperature and ionization was 10 eV and 1.0, respectively, which agrees with our models. In the forward scattering data, we observed an inelastic feature in the Thomson spectrum that our models currently do not reproduce, so there is food for thought. We are in the process of writing these results up. Depending on if we can combine the Bragg and Thomson data or not, we plan to publish them in a single paper (e.g. Nature or Science) or as two separate papers (e.g. two Phys. Rev. Lett.). We will present the first analysis of the results at the APS Plasma Meeting in November 2010. We had a fantastic experience performing our experiment at the LCLS, and we are grateful to the beamline scientists and all the support personnel for enabling this experiment. A major hurdle was the very short transition time of two days, which despite all our preparations did not give us sufficient time to test the full system before the start of the beam time. We further were not able to make optimal use of the beam time since we had to exchange samples in the middle of the 36-hours shift. An additional 12-hours break could have avoided this. Finally, our experiment would have benefitted from the best possible focus, but 5 shifts do not allow performing the experiment while fine-tuning the focusing optics.

  19. Quantum State and Process Tomography of Energy Transfer Systems via Ultrafast Spectroscopy

    E-Print Network [OSTI]

    Joel Yuen-Zhou; Jacob J. Krich; Masoud Mohseni; Alán Aspuru-Guzik

    2011-10-28T23:59:59.000Z

    The description of excited state dynamics in multichromophoric systems constitutes both a theoretical and experimental challenge in modern physical chemistry. An experimental protocol which can systematically characterize both coherent and dissipative processes at the level of the evolving quantum state of the chromophores is desired. In this article, we show that a carefully chosen set of polarization controlled two-color heterodyned photon-echo experiments can be used to reconstruct the time-evolving density matrix of the one-exciton manifold of a heterodimer. This possibility in turn allows for a complete description of the excited state dynamics via quantum process tomography (QPT). Calculations on the dimer show that QPT can reveal rich information about system-bath interactions, which otherwise appear nontrivially hidden in the polarization monitored in standard four-wave mixing experiments. Our study presents a novel method for analyzing condensed phase experiments with a quantum information processing perspective.

  20. Substructured multibody molecular dynamics.

    SciTech Connect (OSTI)

    Grest, Gary Stephen; Stevens, Mark Jackson; Plimpton, Steven James; Woolf, Thomas B. (Johns Hopkins University, Baltimore, MD); Lehoucq, Richard B.; Crozier, Paul Stewart; Ismail, Ahmed E.; Mukherjee, Rudranarayan M. (Rensselaer Polytechnic Institute, Troy, NY); Draganescu, Andrei I.

    2006-11-01T23:59:59.000Z

    We have enhanced our parallel molecular dynamics (MD) simulation software LAMMPS (Large-scale Atomic/Molecular Massively Parallel Simulator, lammps.sandia.gov) to include many new features for accelerated simulation including articulated rigid body dynamics via coupling to the Rensselaer Polytechnic Institute code POEMS (Parallelizable Open-source Efficient Multibody Software). We use new features of the LAMMPS software package to investigate rhodopsin photoisomerization, and water model surface tension and capillary waves at the vapor-liquid interface. Finally, we motivate the recipes of MD for practitioners and researchers in numerical analysis and computational mechanics.

  1. (Quantum Molecular Dynamics Method) (Classical Molecular Dynamics Method)

    E-Print Network [OSTI]

    Maruyama, Shigeo

    1-1 (Quantum Molecular Dynamics Method) (Classical Molecular Dynamics Method) 2) Verlet(Verlet's leap frog) (17)(18) ( ) i i ii m t t t t t t F vv + -= + 22 (17

  2. Graduate Studies Department of Physics

    E-Print Network [OSTI]

    Fabry, Frederic

    Graduate Studies in Physics Department of Physics Ernest Rutherford Physics Building Mc - 8434 Email: secretariat@physics.mcgill.ca Web: http://www.physics.mcgill.ca McGill Physics 2011 ­ 2012 mot de bienvenue . . . . . . . . . . . . . . . . . . . . . 1 The Challenge of Physics

  3. Molecular Gas in Early-type Galaxies

    E-Print Network [OSTI]

    Alatalo, Katherine Anne

    2012-01-01T23:59:59.000Z

    toward the center (first seen in the molecular gas in A+3.4 Molecular Gas Mass . . . . . . .of the molecular gas . . . . . . . . . . 2.4.3 Mass of

  4. B13+: Photodriven Molecular Wankel Engine. | EMSL

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

    B13+: Photodriven Molecular Wankel Engine. B13+: Photodriven Molecular Wankel Engine. Abstract: Synthetic molecular motors that are capable of delivering controlled movement upon...

  5. Molecular Biology DEGREE PROGRAMME

    E-Print Network [OSTI]

    Levi, Ran

    to the course co-ordinator for that module (See University Catalogue of Courses or SMS World Wide Web Pages in molecular biology have a wide range of career options, including virtually all areas of biology, medicine with mastering statistics, graphics and word processing software packages. General Enquiries The Degree Programme

  6. Breaking the Attosecond, Angstrom and TV/M Field Barriers with Ultra-Fast Electron Beams

    SciTech Connect (OSTI)

    Rosenzweig, James; Andonian, Gerard; Fukasawa, Atsushi; Hemsing, Erik; Marcus, Gabriel; Marinelli, Agostino; Musumeci, Pietro; O'Shea, Brendan; O'Shea, Finn; Pellegrini, Claudio; Schiller, David; Travish, Gil; /UCLA; Bucksbaum, Philip; Hogan, Mark; Krejcik, Patrick; /SLAC; Ferrario, Massimo; /INFN, Rome; Full, Steven; /Penn State U.; Muggli, Patric; /Southern California U.

    2012-06-22T23:59:59.000Z

    Recent initiatives at UCLA concerning ultra-short, GeV electron beam generation have been aimed at achieving sub-fs pulses capable of driving X-ray free-electron lasers (FELs) in single-spike mode. This use of very low Q beams may allow existing FEL injectors to produce few-100 attosecond pulses, with very high brightness. Towards this end, recent experiments at the LCLS have produced {approx}2 fs, 20 pC electron pulses. We discuss here extensions of this work, in which we seek to exploit the beam brightness in FELs, in tandem with new developments in cryogenic undulator technology, to create compact accelerator-undulator systems that can lase below 0.15 {angstrom}, or be used to permit 1.5 {angstrom} operation at 4.5 GeV. In addition, we are now developing experiments which use the present LCLS fs pulses to excite plasma wakefields exceeding 1 TV/m, permitting a table-top TeV accelerator for frontier high energy physics applications.

  7. General Syllabus Physics 45100

    E-Print Network [OSTI]

    Lombardi, John R.

    General Syllabus Physics 45100 Thermodynamics and Statistical Physics Designation: Undergraduate Catalog description: 45100: Thermodynamics and Statistical Physics Temperature; equation of state; work and statistical mechanics; low-temperature physics; the Third Law. 3 HR./Wk.; 3 CR. Prerequisites: Physics 35100

  8. Shock and Detonation Physics at Los Alamos National Laboratory

    SciTech Connect (OSTI)

    Robbins, David L [Los Alamos National Laboratory; Dattelbaum, Dana M [Los Alamos National Laboratory; Sheffield, Steve A [Los Alamos National Laboratory

    2012-08-22T23:59:59.000Z

    WX-9 serves the Laboratory and the Nation by delivering quality technical results, serving customers that include the Nuclear Weapons Program (DOE/NNSA), the Department of Defense, the Department of Homeland Security and other government agencies. The scientific expertise of the group encompasses equations-of-state, shock compression science, phase transformations, detonation physics including explosives initiation, detonation propagation, and reaction rates, spectroscopic methods and velocimetry, and detonation and equation-of-state theory. We are also internationally-recognized in ultra-fast laser shock methods and associated diagnostics, and are active in the area of ultra-sensitive explosives detection. The facility capital enabling the group to fulfill its missions include a number of laser systems, both for laser-driven shocks, and spectroscopic analysis, high pressure gas-driven guns and powder guns for high velocity plate impact experiments, explosively-driven techniques, static high pressure devices including diamond anvil cells and dilatometers coupled with spectroscopic probes, and machine shops and target fabrication facilities.

  9. Cavity-enhanced field-free molecular alignment at high repetition rate

    E-Print Network [OSTI]

    Benko, Craig; Allison, Thomas K; Labaye, François; Ye, Jun

    2015-01-01T23:59:59.000Z

    Extreme ultraviolet frequency combs are a versatile tool with applications including precision measurement, strong-field physics, and solid-state physics. Here we report on an application of extreme ultraviolet frequency combs and their driving lasers to studying strong-field effects in molecular systems. We perform field-free molecular alignment and high-order hamonic generation with aligned molecules in a gas jet at 154 MHz repetition rate using a high-powered optical frequency comb inside a femtosecond enhancement cavity. The cavity-enhanced system provides means to reach suitable intensities to study field-free molecular alignment and enhance the observable effects of the molecule-field interaction. We observe modulations of the driving field, arising from the nature of impulsive stimulated Raman scattering responsible for coherent molecular rotations. We foresee impact of this work on the study of molecule-based strong-field physics, with improved precision and a more fundamental understanding of the int...

  10. The Effects of Molecular Weight and Temperature on the Kinetic Friction of Silicone Rubbers

    E-Print Network [OSTI]

    Chaudhury, Manoj K.

    The Effects of Molecular Weight and Temperature on the Kinetic Friction of Silicone Rubbers rubber products were performed for the sole purpose of tabulating properties for consumers with the purpose of understanding the physics of rubber sliding. Quantita- tive physical analysis began

  11. FPGA Acceleration of Discrete Molecular Dynamics Simulation

    E-Print Network [OSTI]

    Herbordt, Martin

    ' & $ % FPGA Acceleration of Discrete Molecular Dynamics Simulation Joshua Model Thesis submitted UNIVERSITY COLLEGE OF ENGINEERING Thesis FPGA Acceleration of Discrete Molecular Dynamics Simulation Acceleration of Discrete Molecular Dynamics Simulation Joshua Model ABSTRACT Molecular dynamics simulation

  12. Outflow Driven Turbulence in Molecular Clouds

    E-Print Network [OSTI]

    Jonathan J. Carroll; Adam Frank; Eric G. Blackman; Andrew J. Cunningham; Alice C. Quillen

    2008-05-30T23:59:59.000Z

    In this paper we explore the relationship between protostellar outflows and turbulence in molecular clouds. Using 3-D numerical simulations we focus on the hydrodynamics of multiple outflows interacting within a parsec scale volume. We explore the extent to which transient outflows injecting directed energy and momentum into a sub-volume of a molecular cloud can be converted into random turbulent motions. We show that turbulence can readily be sustained by these interactions and show that it is possible to broadly characterize an effective driving scale of the outflows. We compare the velocity spectrum obtained in our studies to that of isotropically forced hydrodynamic turbulence finding that in outflow driven turbulence a power law is indeed achieved. However we find a steeper spectrum (beta ~ 3) is obtained in outflow driven turbulence models than in isotropically forced simulations (beta ~ 2). We discuss possible physical mechanisms responsible for these results as well and their implications for turbulence in molecular clouds where outflows will act in concert with other processes such as gravitational collapse.

  13. Photoelectron Angular Distribution and Molecular Structure in...

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

    Angular Distribution and Molecular Structure in Multiply Charged Anions. Photoelectron Angular Distribution and Molecular Structure in Multiply Charged Anions. Abstract:...

  14. Molecular conformations, interactions, and properties associated...

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

    Molecular conformations, interactions, and properties associated with drug efficiency and clinical performance among VEGFR TK inhibitors Molecular conformations, interactions, and...

  15. New results in atomic physics at the Advanced Light Source

    SciTech Connect (OSTI)

    Schlachter, A.S.

    1995-01-01T23:59:59.000Z

    The Advanced Light Source is the world's first low-energy third-generation synchrotron radiation source. It has been running reliably and exceeding design specifications since it began operation in October 1993. It is available to a wide community of researchers in many scientific fields, including atomic and molecular science and chemistry. Here, new results in atomic physics at the Advanced Light Source demonstrate the opportunities available in atomic and molecular physics at this synchrotron light source. The unprecedented brightness allows experiments with high flux, high spectral resolution, and nearly 100% linear polarization.

  16. Argonne Physics Division - ATLAS

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

    (or 630-252-1911 on cell phones) Safety Aspects of radiation safety at ATLAS: Health Physics Coverage at ATLAS is provided by Argonne National Laboratory. Health Physics...

  17. LANL | Physics | LDRD

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

    directed research and development funding at Los Alamos National Laboratory. Physics Division, as the major source of innovation in experimental physical science at Los...

  18. ORISE: Health Physics Training

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

    Health Physics Training Student performs an analysis during an ORAU health physics training course Training and educating a highly skilled workforce that can meet operational...

  19. Nuclear Physics: Recent Talks

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

    Free Electron Laser (FEL) Medical Imaging Physics Topics Campaigns Meetings Recent Talks Archived Talks Additional Information Computing at JLab Operations Logbook Physics Topics:...

  20. Nuclear Physics: Campaigns

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

    Free-Electron Laser (FEL) Medical Imaging Physics Topics Campaigns The Structure of the Nuclear Building Blocks The Structure of Nuclei Symmetry Tests in Nuclear Physics Meetings...