High-efficiency energy extraction in backward-wave Raman scattering

Pump depletions of 70–75% have been demonstrated for a KrF-laser-driven, methane-gas-filled backward Raman amplifier and are in agreement with predictions of the Frantz-Nodvik saturated-amplifier model. The associated counterpropagating Stokes laser intensity is determined to be ≳3.5 times that of the pump; the corresponding pulse compression ratio is ≈5.