Self-compression of stimulated Raman backscattering by a flying focus.

Wu, Z; Zuo, Y; Zhang, Z; Wang, X; Mu, J; Wang, X D; Hu, B; Su, J et al. · Phys Rev E · 2022

basic_science · Level V

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Abstract

The regime of self-compression has been proposed for plasma-based backward Raman amplification upon a flying focus. By using a pumping focus moving with a speed equal to the group velocity of stimulated Raman backscattering (SRBS), only a short part of SRBS which always synchronizes with the flying focus can be amplified. Therefore, instead of a short pulse, plasma noise or a long pulse can seed the BRA amplifiers. Here we demonstrate the regime by 2D particle-in-cell simulations, showing that the pump pulse is compressed from 26 ps to 116 fs, with an output amplitude comparable with the case of a well-synchronized short seed. As only one laser pulse is used in the simulation, the results present a significant path to simplify the Raman amplifiers.