A5088556721- Laser-Matter Interactions and Applications
- Laser-Plasma Interactions and Diagnostics
- Advanced Fiber Laser Technologies
- Laser-induced spectroscopy and plasma
- Laser Design and Applications
- Atomic and Molecular Physics
- Laser Material Processing Techniques
- Optical Coatings and Gratings
- Ocular and Laser Science Research
- Solid State Laser Technologies
- Photonic Crystal and Fiber Optics
- Gas Dynamics and Kinetic Theory
- Photorefractive and Nonlinear Optics
- Dust and Plasma Wave Phenomena
- Turbomachinery Performance and Optimization
- Semiconductor Lasers and Optical Devices
- Diamond and Carbon-based Materials Research
- Ionosphere and magnetosphere dynamics
- Spectroscopy and Laser Applications
- Plasma Diagnostics and Applications
- Adaptive optics and wavefront sensing
- Heat Transfer and Boiling Studies
- Photonic and Optical Devices
- Optical Network Technologies
- Advanced X-ray Imaging Techniques
University of Rochester
2018-2024
Energetics (United States)
2018-2023
Applied Energetics (United States)
2017-2023
We propose a new laser amplifier scheme utilizing stimulated Raman scattering in plasma conjunction with ``flying focus''---a chromatic focusing system combined chirped pump beam that provides spatiotemporal control over the pump's focal spot. Pump intensity isosurfaces are made to propagate at $v=\ensuremath{-}c$ so as be sync injected counterpropagating seed pulse. By setting interaction region just above ionization threshold of background gas, an wave is produced travels fixed distance...
Abstract Optical parametric chirped-pulse amplification implemented using multikilojoule Nd:glass pump lasers is a promising approach for producing ultra-intense pulses (>10 23 W/cm 2 ). We report on the MTW-OPAL Laser System, an optical amplifier line (OPAL) pumped by Nd:doped portion of multi-terawatt (MTW) laser. This midscale prototype was designed to produce 0.5-PW with technologies scalable tens petawatts. Technology choices made were guided longer-term goal two full-scale OPALs...
Pre-pedestal generation is observed in a 0.35-PW laser front end coming from post-pedestal via instantaneous gain and pump depletion an optical parametric amplifier during chirped-pulse amplification. Generalized simulations show how this effect arises nonlinearity applies to all chirped-pulse-amplification systems with post-pedestal. An experiment minimizing the of B-integral used isolate study newly conversion continuous into pre-pedestal. Matching numerical confirm experimental results...
An advanced focusing scheme, called a “flying focus,” uses chromatic system combined with broadband laser pulse its colors arranged in time to propagate high intensity focus over distance that can be much greater than Rayleigh length while decoupling the speed at which peak propagates from group velocity. The flying generates short effective duration small diameter focal spot co- or counter-propagates along optical axis any Experiments validating concept measured subluminal (−0.09c)...
Plasma amplifiers offer a route to side-step limitations on chirped pulse amplification and generate laser pulses at the power frontier. They compress long by transferring energy shorter via Raman or Brillouin instabilities. We present an extensive kinetic numerical study of three-dimensional parameter space for case. Further particle-in-cell simulations find optimal seed parameters experimentally relevant constraints. The high-efficiency self-similar behavior is observed only seeds than...
Combining a chirped laser pulse with chromatic lens yields flying focus—a focus that moves dynamically in time. This provides control over the propagation of peak intensity within an extended focal region can be many times larger than system's Rayleigh length. Any velocity is achievable, including backward relative to direction. Previous simulation results have shown beam create counter-propagating ionization wave and subsequently pump frequency-downshifted via stimulated Raman scattering...
The effects of pulse compressor grating misalignment on duration and focusability are simulated for chirped-pulse–amplification systems varying bandwidths, beam sizes, groove densities, incident angles. Tilt-alignment tolerances specified based a 2 drop in focused intensity, illustrating how scale with bandwidth size, which scales energy when transformed via known damage thresholds. Grating-alignment tolerance scaling density incident/diffracted angles is investigated applied to...
The rapid evolutions of the electron density and temperature in a laser-produced plasma were measured using collective Thomson scattering. Unprecedented picosecond time resolution, enabled by pulse-front-tilt compensated spectrometer, revealed transition plasma-wave dynamics from an initially cold, collisional state to quasistationary, collisionless state. Thomson-scattering spectra compared with theoretical calculations fluctuation spectrum either conventional Bhatnagar-Gross-Krook (BGK)...
We present a theoretical and experimental analysis of the signal phase introduced by pump-beam wavefront spatial profile during optical parametric amplification (OPA) process. The theory predicts appearance an additional in amplified beam that is proportional to derivative wavefront. effect on signal-beam also investigated. Our experiments tested these predictions comparing before after multi-joule broadband OPA. measured was shown have expected dependence These results can be considered...
Powerful ultrafast lasers with wavelengths above 1 μm are in demand to create attosecond pulses and ultra-intense laser sources. A promising technology achieve these sources uses the by-product from an optical parametric chirped-pulse amplifier, known as idler. Compression of idler high peak powers requires a grism stretcher grating compressor. Grism stretchers have many more design parameters than conventional stretchers, complicating process. This paper presents method for designing...
Raman back-scatter from an under-dense plasma can be used to compress laser pulses, as shown by several previous experiments in the optical regime. A short seed pulse counter-propagates with a longer pump and energy is transferred shorter via stimulated scattering. The robustness of scheme non-ideal density conditions demonstrated through particle-in-cell simulations. scale invariance ensures that compression XUV pulses free electron also possible, further output 300 as, typical fourth...
Optical parametric chirped-pulse-amplification produces two broadband pulses, a signal and an idler, that can both provide peak powers >100 GW. In most cases the is used, but compressing longer-wavelength idler opens up opportunities for experiments where driving laser wavelength key parameter. This paper will describe several subsystems were added to petawatt class, Multi-Terawatt optical amplifier line (MTW-OPAL) at Laboratory Laser Energetics address long-standing issues introduced by use...
Optical parametric chirped-pulse amplification (OPCPA) using high-energy Nd:glass lasers has the potential to produce ultra-intense pulses (>1023 W/cm2). We report on performance of final high-efficiency amplifier in an OPCPA system based large-aperture (63 × 63-mm2) partially deuterated potassium dihydrogen phosphate (DKDP) crystals. The seed beam (180-nm bandwidth, 110 mJ) was provided by preceding stages. A maximum pump-to-signal conversion efficiency 41% and signal energy up 13 J were...
We used COMSOL Multiphysics to design a prototype actively cooled "flow-cell" substrate targeted at high-average-power applications, fabricated the from cordierite ceramic, and tested under load in our thermal loading test stand. Sub-aperture testing revealed average-power handling up 3.88-W/cm2 absorbed power density, excellent agreement with model predictions. Gratings on 2-in.-diam coupons were subjected laser-damage showed damage threshold of 250 mJ/cm2.
Ultra-intense laser systems are being developed by a number of institutions to use the full potential deuterated potassium dihydrogen phosphate (DKDP) for high-energy optical parametric chirped-pulse amplification (OPCPA) [1] – [3] . Noncollinear amplifiers (NOPA's) made large DKDP crystals produce broadband gain supporting pulses as short 10 fs. Although OPCPA is now routinely used front-end technology, scaling >100 J still an active area research. This paper reports on MTW-OPAL Laser...
Temporal contrast pre-pedestal growth from a post-pedestal via optical parametric amplifier saturation is demonstrated for the first time. This mechanism can be limiting factor high-contrast OPCPA systems with an existing post-pedestal.
Multispectral wavefront sensing techniques are employed for single-shot spatiotemporal characterization. Phase diversity and lateral shearing used with a multispectral camera to characterize radial group delay, compressor grating misalignment, optical parametric chirped- pulse-amplification performance.
The impact of mid-spatial-frequency errors in stretcher optics on temporal contrast via spatiotemporal coupling is studied experimentally. Three Offner secondary mirrors are compared, clearly showing degradation resulting from magnetorheological finishing.
This paper describes an alternate mode of operating existing petawatt class laser (MTW-OPAL) to utilize the idler by addressing angular dispersion and spectral phase reversal.
Sub-aperture tests and modeling of a “flow-cell” substrate demonstrated <30-s stabilization time. At full-aperture, 2.6-W/cm 2 absorbed power density, COMSOL predicts >160× improvement in average-power handling 150× reduction warmup time versus passively cooled silica.