Boosting the performance of Brillouin amplification at sub-quarter-critical densities via reduction of parasitic Raman scattering
Brillouin amplification of laser pulses in plasma has been shown to be a promising approach to produce picosecond pulses of petawatt power. A key challenge is preservation of the quality of the amplified pulse, which requires control of parasitic instabilities that accompany the amplification process. At high plasma densities (>cr/4), ponderomotive filamentation has been identified as the biggest threat to the integrity of the amplifying pulse. It has therefore been proposed to perform Brillouin scattering at densities below ncr/4 to reduce the influence of filamentation. However, parasitic Raman scattering can become a problem at such densities, contrary to densities abovemore »