A5059407961- Laser-Plasma Interactions and Diagnostics
- Laser-induced spectroscopy and plasma
- Nuclear Physics and Applications
- Semiconductor Quantum Structures and Devices
- High-pressure geophysics and materials
- Advanced Optical Sensing Technologies
- Optical Systems and Laser Technology
- Laser Design and Applications
- Advancements in Photolithography Techniques
- Advanced Semiconductor Detectors and Materials
- Optical Coatings and Gratings
- Laser-Matter Interactions and Applications
- Magnetic confinement fusion research
- Semiconductor Lasers and Optical Devices
- Quantum Dots Synthesis And Properties
- Optical measurement and interference techniques
- Quantum and electron transport phenomena
- Astronomical Observations and Instrumentation
- Cold Fusion and Nuclear Reactions
- Advanced X-ray and CT Imaging
- Advanced Measurement and Detection Methods
- Advanced Measurement and Metrology Techniques
- Nuclear reactor physics and engineering
- Engineering and Material Science Research
- Advanced X-ray Imaging Techniques
Lawrence Livermore National Laboratory
2015-2024
Los Alamos National Laboratory
2012-2021
CEA DAM Île-de-France
2013-2014
Sandia National Laboratories
2012-2014
General Atomics (United States)
2012-2014
Massachusetts Institute of Technology
2012-2014
Fusion Academy
2012-2014
Fusion (United States)
2012-2014
Rutherford Appleton Laboratory
2014
Université Paris-Sud
2013
We report time-resolved photoluminescence measurements as a function of temperature for InAs quantum dots grown by molecular-beam epitaxy on GaAs(100). As the is increased, decays high-energy side band speed up, while decay times low-energy increase. This increase occurs up to ``drop'' temperature, which increases with decreasing emission energy, beyond decrease. present coupled rate-equation model includes effects thermal from dot states into wetting layer followed transport and recapture,...
We report a reflection high energy electron diffraction study of InAs self-organized quantum dots grown on GaAs (001). observe facet reflections along the [31̄0] and [13̄0] azimuths, which indicate that dot shape is pyramidal with bounding facets corresponding to family four {136} planes. The determined structure, possesses C2v symmetry, quite different both from square-base geometries have been assumed in recent electronic structure calculations, previously proposed structures based upon...
The first inertial confinement fusion implosion experiments with equimolar deuterium-tritium thermonuclear fuel have been performed on the National Ignition Facility. These use 0.17 mg of potential for ignition and significant yield conditions. has fielded as a cryogenic layer inside spherical plastic capsule that is mounted in center cylindrical gold hohlraum. Heating hohlraum 192 laser beams total energy 1.6 MJ produces soft x-ray field 300 eV temperature. ablation pressure produced by...
The National Ignition Facility (NIF) is the world's largest optical instrument, comprising 192 37 cm square beams, each generating up to 9.6 kJ of 351 nm laser light in a 20 ns beam precisely tailored time and spectrum. houses massive (10 m diameter) target chamber within which beams converge onto an ∼1 size for purpose creating conditions needed deuterium/tritium nuclear fusion laboratory setting. A formidable challenge was building NIF precise requirements propagation, commissioning lines,...
Compound parabolic concentrator (CPC) targets are utilized at the National Ignition Facility Advanced Radiographic Capability (NIF-ARC) laser to enhance acceleration of electrons and production high energy photons, for durations 10 ps energies up 2.4 kJ. A large enhancement mean electron (>2 ×) photon brightness (>10×) is found with CPC compared flat targets. Using multiple diagnostic techniques different spatial locations scaling by gold activation data, spectra characterized...
New short-pulse kilojoule, Petawatt-class lasers, which have recently come online and are coupled to large-scale, many-beam long-pulse facilities, undoubtedly serve as very exciting tools capture transformational science opportunities in high energy density physics. These lasers also happen reside a unique laser regime: high-energy (kilojoule), relatively long (multi-picosecond) pulse-lengths, large (10s of micron) focal spots, where their use driving energetic particle beams is largely...
The implosion efficiency in inertial confinement fusion depends on the degree of stagnated fuel compression, density uniformity, sphericity, and minimum residual kinetic energy achieved. Compton scattering-mediated 50--200 keV x-ray radiographs indirect-drive cryogenic implosions at National Ignition Facility capture dynamic evolution as it goes through peak revealing low-mode 3D nonuniformities thicker with lower than simulated. By differencing two taken different times during same...
The National Ignition Facility (NIF) at Lawrence Livermore Laboratory is the first of a kind megajoule-class laser with 192 beams capable delivering over 1.8 MJ and 500TW 351nm light [1], [2]. It has been commissioned operated since 2009 to support wide range missions including study inertial confinement fusion, high energy density physics, material science, laboratory astrophysics. In order advance our understanding, enable short-pulse multi-frame radiographic experiments dense cores cold...
The Crystal Backlighter Imager (CBI) is a quasi-monochromatic, near-normal incidence, spherically bent crystal imager developed for the National Ignition Facility (NIF), which will allow inertial confinement fusion capsule implosions to be radiographed close stagnation. This not possible using standard pinhole-based area-backlighter configuration, as self-emission from hotspot overwhelms backlighter signal in final stages of implosion. CBI mitigates broadband hot spot by extremely narrow...
We report a study of the dynamics coherent island formation in InAs/GaAs films grown by molecular beam epitaxy. A comparison temperature dependence critical layer thickness for islanding between migration-enhanced and continuous growth modes confirms that surface adatom diffusion indium desorption are controlling processes which determine variation measured with temperature. find under conditions is significant, transition reversible, provides new way to transition. Applying this technique,...
Relativistic electron temperatures were measured from kilojoule, subrelativistic laser-plasma interactions. Experiments show an order of magnitude higher than expected a ponderomotive scaling, where up to 2.2 MeV generated using intensity 1×10^{18}W/cm^{2}. Two-dimensional particle-in-cell simulations suggest that electrons gain superponderomotive energies by stochastic acceleration as they sample large area rapidly changing laser phase. We demonstrate such high are possible intensities...
We report a photoluminescence study of self-assembled InAs islands subjected to in situ annealing prior the growth capping layer. A distinctive double-peak feature is observed spectra annealed samples. The power dependence reveals that emission associated with ground-state transition two different size branches. This observation agrees previous study, which demonstrated island distribution bifurcates during post-growth annealing. temperature intensities from samples bimodal distributions...
A spectroscopic, diffraction based technique is proposed in this paper as an alternative solution for overlay metrology technology nodes below 90 nanometers. This novel extracts alignment error from broadband efficiency of specially designed targets real-time. Feasibility the studied a front-end process flow by measuring grating printed on series wafers which were intentionally mis-processed to introduce inter-die (grid) level programmed errors. Correlation conventional imaging measurements...
The advanced radiographic capability (ARC) laser system, part of the National Ignition Facility (NIF) at Lawrence Livermore Laboratory, is a short-pulse integrated into NIF. ARC designed to provide adjustable pulse lengths <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mo>∼</mml:mo> </mml:mrow> <mml:mn>1</mml:mn> <mml:mo>−</mml:mo> <mml:mn>38</mml:mn> <mml:mspace width="thickmathspace"/> <mml:mi...
The requirements for beam and target alignment successful ignition experiments on the National Ignition Facility (NIF) are stringent: average of beams to must be within 25 μm. Beam achieved with Target Alignment Sensor (TAS). TAS is a precision optical device that inserted into chamber center facilitate both alignment. It incorporates two camera views (upper/lower side) mounted each stage assemblies (jaws) view align target. also large mirror reflect onto upper/lower cameras located in using...
As lithographic technology drives the minimum integrated circuit feature size toward 0.1 /spl mu/m and below, process tolerances for critical-dimension profile excursion are becoming increasingly demanding. In response, optical critical dimension metrology (OCD), an optical-wavelength light-diffraction technique, is emerging as a fast, accurate, nondestructive sub-100-nm linewidth monitor. such, detailed understanding of correlation between OCD existing tools required. Correlation CD...
We report in situ photoluminescence and ex Fourier transform infrared spectra of nanoscale silicon clusters exposed to atomic hydrogen, molecular oxygen, humidified argon. Comparisons between absorption fresh aged samples indicate that efficiency is correlated with a stoichiometric oxide shell the presence Si dangling bond passivants at core/oxide interface. Photoluminescence quenching demonstrated efficiently luminescing upon exposure hydrogen recovery occurring subsequent air. The partial...
The advanced radiographic capability located at the National Ignition Facility (NIF) uses high intensity, short pulse lasers to create bright photon sources for diagnosing energy density experiments. There are needs a multi-frame time-resolved MeV gamma diagnostic experiments on NIF with sub-nanosecond resolution. A series of demonstrated measurements x-ray spectra resolved time separation few nanoseconds through use gas Cherenkov detectors. two-pulse experiment found 30% reduction in...
The National Ignition Facility (NIF) utilizes 192 high-energy laser beams focused with enough power and precision on a hydrogen-filled spherical, cryogenic target to potentially initiate fusion reaction. NIF has been operational for six years during that time, thousands of successful firings or shots have executed. Critical instrument measurements camera images are carefully recorded each shot. result is massive complex database 'big data' archive can be used investigate the state system at...
Optical critical dimension metrology (OCD), an optical-wavelength light-diffraction technique, is currently undergoing industry-wide evaluation as a fast, accurate, and non-destructive sub-100 nm line-width monitor. The spectroscopic, zeroth-order diffraction signature obtained from printed grating allows extraction of structural information, such linewidth, sidewall angle, profile characteristics. OCD spectrometer compact designed for integration into etch tools lithography tracks....
The Automatic Alignment system in the National Ignition Facility is responsible for aligning 192 laser beams using camera sensor images. This paper reviews some of image processing algorithms that generate crucial alignment positions.
The Advance Radiographic Capability (ARC) at the National Ignition Facility (NIF) is a laser system that employs up to four petawatt (PW) lasers produce sequence of short pulses generate X-rays which backlight high-density inertial confinement fusion (ICF) targets. ARC designed multiple, sequential X-ray images by using eight back lighters. will be used examine compression and ignition cryogenic deuterium-tritium target with tens-of-picosecond temporal resolution during critical phases an...