Phys.org January 31, 2023
High power lasers have become useful scientific tools, but their large size is determined by their low damage-threshold optical media. A more robust and compact medium for amplifying and manipulating intense laser pulses is plasma. An international team of researchers (UK, Germany, Portugal) has demonstrated, experimentally and through simulations, that few-millijoule, ultra-short seed pulses interacting with 3.5-J counter-propagating pump pulses in plasma, stimulate back-scattering of nearly 100 mJ pump energy with high intrinsic efficiency, when detuned from Raman resonance. This is due to scattering off a plasma Bragg grating formed by ballistically evolving ions. Electrons are bunched by the ponderomotive force of the beat-wave, which produces space-charge fields that impart phase correlated momenta to ions. They inertially evolve into a volume Bragg grating that backscatters a segment of the pump pulse. This, ultra-compact, two-step, inertial bunching mechanism can be used to manipulate and compress intense laser pulses. The team also observed stimulated Compton (kinetic) and Raman backscattering. According to the researchers this more compact and much more robust and could provide a paradigm shift in high power lasers, which would stimulate new directions of research…read more. Open Access TECHNICAL ARTICLE
Main experimental results. Credit: Communications Physics volume 6, Article number: 9 (2023)