Prepulse suppression and optimization of backward Raman amplification with a chirped pump laser beam
R. Nuter and V. Tikhonchuk
Accepted
Two-dimensional "Particle In Cell" (PIC) simulations have been performed to demonstrate how chirping the pump laser beam can make the seed backward Raman amplification more efficient. The new PIC code OCEAN is detailed and validated with theoretical analysis of the 3-waves coupling. A particular attention is devoted to the impact of numerical noise on Raman scattering. Once the numerical parameters set, 1D and 2D simulations exhibit the ability to suppress the pedestal pulse preceding the amplified seed laser beam and to lower the spontaneous Raman scattering by appropriately choosing the pump chirp value.