A5071692905- Laser-Plasma Interactions and Diagnostics
- Nuclear Physics and Applications
- Laser-Matter Interactions and Applications
- Laser-induced spectroscopy and plasma
- High-pressure geophysics and materials
- Atomic and Subatomic Physics Research
- Advanced X-ray Imaging Techniques
- Radiation Detection and Scintillator Technologies
- Radiation Effects in Electronics
- Radiation Therapy and Dosimetry
- Spectroscopy Techniques in Biomedical and Chemical Research
- Near-Field Optical Microscopy
- Photorefractive and Nonlinear Optics
- Surface and Thin Film Phenomena
- Solid State Laser Technologies
- Laser Design and Applications
- X-ray Diffraction in Crystallography
- Thermal Radiation and Cooling Technologies
- Quantum optics and atomic interactions
- Photonic Crystal and Fiber Optics
- Advanced Radiotherapy Techniques
- Pulsed Power Technology Applications
- Semiconductor Quantum Structures and Devices
- Organic Electronics and Photovoltaics
- Gold and Silver Nanoparticles Synthesis and Applications
The University of Texas at Austin
2014-2020
Pyramid Technical Consultants (United States)
2013-2019
Institute for Technical Physics and Materials Science
1967-1970
Czech Academy of Sciences, Institute of Physics
1963
Central Research Institute
1960-1963
Institute for Solid State Physics and Optics
1960
Solid State Physics Laboratory
1960
Institute for Physics
1960
Theoretical calculations are presented which show that the enhancement predicted by particle plasmon model of surface-enhanced Raman scattering is limited radiation damping. The damping becomes more severe as size increases, while produced small particles surface scattering. Good agreement between theory and experimental measurements wavelength dependence on lithographically microstructures found when taken into account.
Ion beams exhibit a finite range and an inverted depth–dose profile, the Bragg peak. These favorable physical properties allow excellent tumor–dose conformality. However, they introduce sensitivity to uncertainties. Although these uncertainties are typically taken into account in treatment planning, delivery of intended dose patient has be ensured daily prevent underdosage tumor or overdosage surrounding critical structures. Thus, imaging techniques play increasingly important role for...
We report measurements of the scattering and absorption 3.39-\ensuremath{\mu}m light by electron-hole drops in Ge. An unexpected Fabry-Perot effect our samples allows us to measure not only drop size but also their absolute concentration optical indices refraction condensate.
When an ultrashort laser pulse is tightly focused to a size approaching its central wavelength, the properties of spot diverge from diffraction limited case. Here we report on this change in behavior Petawatt class beam by F/1 off-axis paraboloid (OAP). Considering effects residual aberration, spatial profile near field and pointing error, estimate deviation peak intensities ideal We verify that estimated intensity values are within acceptable error range measured values. With added...
We have completed a pulse contrast upgrade on the Texas Petawatt Laser. This improvement enables use of thin and reduced mass targets for ion acceleration, reduces pre-plasma effects all experiments. The new design starts with two BBO-based OPCPA stages pumped by an optically synchronized 8-ps laser. These amplify slightly chirped few ps pulses six orders magnitude. Next there are LBO-based that 4 ns pulses. With much less gain than before, parametric fluorescence has been about three Prior...
Abstract Radiographic imaging with x-rays and protons is an omnipresent tool in basic research applications industry, material science medical diagnostics. The information contained both modalities can often be valuable principle, but difficult to access simultaneously. Laser-driven solid-density plasma-sources deliver kinds of radiation, mostly single have been explored for applications. Their potential bi-modal radiographic has never fully realized, due problems generating appropriate...
We report on experiments irradiating isolated plastic spheres with a peak laser intensity of 2-3×10^{20}Wcm^{-2}. With focal spot size 10 μm full width half maximum (FWHM) the sphere diameter was varied between 520 nm and 19.3 μm. Maximum proton energies ∼25 MeV are achieved for targets matching in or being slightly smaller. For smaller kinetic energy distributions protons become nonmonotonic, indicating change accelerating mechanism from ambipolar expansion towards regime dominated by...
The dosimetric advantages of ion therapy come at the cost an increased sensitivity to range inaccuracies in treatment planning and delivery stages. This prompts development imaging techniques capable accurate assessment relative stopping power (RSP). We investigate carbon-ion based on a prototype integration-mode detector working as telescope. Experiments were conducted Heidelberg Ion-Beam Therapy Center with active pencil beam scanning. aim this article is experimentally operate system...
We convert a GeV laser-plasma electron accelerator into compact femtosecond-pulsed $γ$-ray source by inserting $100 μ$m-thick glass plate $\sim3$ cm after the exit. With near-unity reliability, and requiring only crude alignment, this plasma mirror retro-reflected spent drive laser pulses (photon energy $\hbarω_L = 1.17$ eV) with $>50\%$ efficiency back onto trailing electrons (peak Lorentz factor $1000 < γ_e 4400$), creating an optical undulator that generated $\sim10^8 γ$-ray photons...
Previous work has demonstrated the use of a plasma mirror (PM), after laser-plasma accelerator (LPA), for generating Compton γ-rays by retro-reflecting spent laser pulse into just-accelerated electrons. Here, we investigate PM to stimulate backscatter (CBS) from Texas Petawatt (TPW) it driven cm-scale, GeV LPA. A comparative analysis between electron and CBS pointing divergence reveals strong agreement, shot-to-shot, suggesting reliable, non-invasive extension GeV-beam metrology. Our...
We generate a collimated (<1mrad) beam of gamma rays that penetrate several centimeters lead by retro-reflecting petawatt laser pulse onto trailing ~2 GeV electrons with plasma mirror after driving laser-plasma accelerator.
With a low repetition rate petawatt-class laser system, effective data collection requires repeatable performance, and even more importantly experimenters need to accurately know the parameters of each pulse. The presentation describes challenges measuring ultrahigh peak power pulse parameters, how we address them, performance variance achieved on Texas Petawatt Laser. Pulse duration, profile, spectrum, energy, plus system prepulse contrast are discussed. Article not available.
We exploited the Faraday effect to imprint polarization shifts on a transverse probe that captured structure of GeV laser-plasma accelerator. Our measurements suggested plasma bubble diameter ≈ 50.8±10.1 μm.
ΓRelativistic laser-plasma interactions as drivers for intense and energetic bursts of proton, electron photon radiation have been studied more than a decade [1,2,3]. Much the attention is driven by their potential use in medical physics, to build compact affordable sources diagnostics therapy. So far, these efforts were focused on single species radiation, meaning either ions, electrons or photons, whilst regarding respective other disturbance [4,5,6].Our experiments make Texas Petawatt...