A5014204937- Laser-Plasma Interactions and Diagnostics
- Laser-Matter Interactions and Applications
- Advanced X-ray Imaging Techniques
- Laser-induced spectroscopy and plasma
- High-pressure geophysics and materials
- Nuclear Physics and Applications
- Atomic and Molecular Physics
- Advanced X-ray and CT Imaging
- Laser Design and Applications
- Ocular and Laser Science Research
- Medical Imaging Techniques and Applications
- Blood transfusion and management
- Laser Material Processing Techniques
- Ion-surface interactions and analysis
- Particle Accelerators and Free-Electron Lasers
- Spectroscopy and Laser Applications
- Dupuytren's Contracture and Treatments
- Optical Systems and Laser Technology
- Tardigrade Biology and Ecology
- Advanced Fiber Laser Technologies
- Advanced Optical Sensing Technologies
- Foot and Ankle Surgery
- Rare-earth and actinide compounds
- Medical Research and Treatments
- Orthopedic Surgery and Rehabilitation
University of Nebraska–Lincoln
2012-2022
Lomonosov Moscow State University
2009-2012
Moscow State University
2009
We report the generation of MeV x rays using an undulator and accelerator that are both driven by same 100-terawatt laser system. The pulse driving scattering independently optimized to generate a high energy electron beam ($>200\text{ }\text{ }\mathrm{MeV}$) maximize output x-ray brightness. total photon number was measured be $\ensuremath{\sim}1\ifmmode\times\else\texttimes\fi{}{10}^{7}$, source size $5\text{ }\ensuremath{\mu}\mathrm{m}$, divergence angle $\ensuremath{\sim}10\text{...
Gamma-ray photons with energy >9 MeV were produced when second-harmonic-generated laser light (3 eV) inverse-Compton-scattered from a counterpropagating relativistic (∼450 MeV) laser-wakefield-accelerated electron beam. Two pulses the same system used: one to accelerate electrons and scatter. Since two play very different roles in γ-ray generation process, thus have requirements, novel was developed. It separately independently optimized optical properties of pulses. This approach also...
We report the results of experiments on laser-wakefield acceleration in a novel two-stage gas target with independently adjustable density and atomic-composition profiles. were able to tailor these profiles way that led separation processes electron injection permitted independent control both. This resulted generation stable, quasimonoenergetic beams central energy tunable 50--300 MeV range. For first time, we are beam charge spread over entire tunability
Stable operation of a laser-plasma accelerator near the threshold for electron self-injection in blowout regime has been demonstrated with 25--60 TW, 30 fs laser pulses focused into 3--4 millimeter length gas jet. Nearly Gaussian shape and high nanosecond contrast pulse appear to be critically important controllable, tunable generation 250--430 MeV bunches low-energy spread, $\ensuremath{\sim}10\text{ }\text{ }\mathrm{pC}$ charge, few-mrad divergence pointing stability, vanishingly small...
Abstract The recent combination of ultra-intense lasers and laser-accelerated electron beams is enabling the development a new generation compact x-ray light sources, coherence which depends directly on beam emittance. Although emittance accelerated can be low, it grow due to effects space charge during free-space propagation. Direct experimental measurement this important property complicated by micron-scale sizes presence intense fields at location where acts. Reported here novel,...
Fourier-transform-limited light pulses were obtained at the laser-plasma interaction point of a 100-TW peak-power laser in vacuum. The spectral-phase distortion induced by dispersion mismatching between stretcher, compressor, and dispersive materials was fully compensated for means an adaptive closed-loop. coherent temporal contrast on sub-picosecond time scale two orders magnitude higher than that without control. This novel phase control capability enabled experimental study dependence...
Interactions of large-amplitude relativistic plasma waves were investigated experimentally by propagating two synchronized ultraintense femtosecond laser pulses in at oblique crossing angles to each other. The electrostatic and electromagnetic fields the colliding acted preaccelerate trap electrons via previously predicted, but untested injection mechanisms ponderomotive drift wake-wake interference. High-quality energetic electron beams produced, also revealing valuable new information...
We report results of an experimental study laser-wakefield acceleration electrons, using a staged device based on double-jet gas target that enables independent injection and stages. This novel scheme is shown to produce stable, quasi-monoenergetic, tunable electron beams. show optimal accelerator performance achieved by systematic variation five critical parameters. For the stage, we amount trapped charge controlled density, composition, laser power. density length jet are found determine...
A repetitive petawatt-class Ti:sapphire laser system operating with high spatial and temporal beam quality is demonstrated. Maximum pulse energy of 30 J obtained via five multi-pass amplification stages. Closed-loop feedback control systems in the domains are used to yield Fourier-transform-limited duration (33.7 fs), diffraction-limited focal spot sizes (with several different tight focusing optics). The parameters have been fully characterized at high-power, monitored real-time, ensure...
Abstract Ultrafast high-brightness X-ray pulses have proven invaluable for a broad range of research. Such are typically generated via synchrotron emission from relativistic electron bunches using large-scale facilities. Recently, significantly more compact sources based on laser-wakefield accelerated (LWFA) beams been demonstrated. In particular, laser-driven sources, where the radiation is by transverse oscillations electrons within plasma accelerator structure (so-called betatron...
We report experimental results on the production and characterization of asymmetric composite supersonic gas flows, created by merging independently controllable flows from multiple nozzles. demonstrate that spatial profiles are adjustable over a large range parameters, including density, density gradient, atomic composition. The were precisely characterized using three-dimensional tomography. creation measurement complex is relevant to numerous applications, ranging laser-produced plasmas...
We demonstrate wavefront correction of terawatt-peak-power laser beams at two distinct and well-separated wavelengths. Simultaneous near diffraction-limited focusability is achieved for both the fundamental (800 nm) second harmonic (400 Ti:sapphire-amplified light. By comparing relative effectiveness various loops, optimal ones are found. different color relies on linear proportionality between their aberrations. This method can enable two-color experiments relativistic intensities.
We present a novel method for measurement of ultrashort electron-bunch duration, in principle, as short zeptosecond (${10}^{\ensuremath{-}21}\text{ }\text{ }\mathrm{s}$). The employs nonlinear Thomson scattering relativistically intense laser light, and takes advantage the dependence coherence scattered light on electron bunch length. validate test its range applicability via simulations by using realistic (nonideal) beams. Due to wide flexibility choice interaction geometry pulse properties...
We recorded the spectrum of delayed secondary electrons ejected from target, which was coated with a layer iron enriched 57Fe isotope to 98%, under its irradiation by fluxes broadband X-ray radiation and fast plasma produced femtosecond laser pulse at an intensity 1017 W cm-2. Maxima were identified energies 5.6, 7.2, 13.6 keV in obtained for delay 90 — 120 ns. The two last-listed maxima owe their origin internal electron conversion isomeric level energy 14.4 lifetime 98 ns K L shells atomic...
High-energy X-rays (HEX-rays) with photon energies on order of 100 keV have attractive characteristics, such as comparably low absorption, high spatial resolution and the ability to access inner-shell states heavy atoms. These properties are advantageous for many applications ranging from studies bulk materials investigation in extreme conditions. Ultrafast X-ray diffraction allows direct imaging atomic dynamics simultaneously its natural time length scale. However, using HEX-rays ultrafast...
We demonstrate a novel approach to the generation of femtosecond electron bunch trains via laser-driven wakefield acceleration. use two independent high-intensity laser pulses, drive, and injector, each creating their own plasma wakes. The interaction pulses wakes results in periodic injection free electrons drive wake several mechanisms, including ponderomotive drift, wake-wake interference, pre-acceleration directly by strong fields. Electron were generated with up 4 quasi-monoenergetic...
An adaptive spectral-phase control method is demonstrated for laser wakefield acceleration of electrons. Phase capability was implemented to experimentally study the dependence on spectral phase intense light.
Quasi monoenergetic and tunable x-ray beams are reported by inverse-Compton scattering from laser wakefield accelerated electrons. The high peak brightness, ultrashort duration, small size of the source make it uniquely suitable for many applications.
A bright, narrow band MeV γ-ray source-ray source based on Thomson scattering using a laser-driven electron accelerator has been developed. We discuss the application of this for selective activation in regions high particle (neutron or gamma) production, with minimal absorption intervening materials.