Focusability in the multi-pump Raman amplification of short laser pulses

Abstract

Spatially combining multiple strong laser beams is a promising concept for achieving ultrahigh laser intensities. Proof-of-principle experiments have been conducted at the National Ignition Facility to report a combination of up to 20 pulses with high energy conversion efficiency. However, the combination process might damage the seed focusability due to mismatch of the seed and pump wavefronts. Here, we investigate the effect of the finite pump beam size on the focusability of the seed pulse. We propose an approach to retain and even improve the seed focusability by specifically arranging multiple pump beams. The results are demonstrated by the numerical solution of coupled nonlinear Schrödinger equations. Our findings also apply to seed amplification by filamented pump pulses.

On parallel laser beam merger in plasmas

“…To illustrate the physics of the parallel beam merger, we conduct NSE simulations using a symmetrized split-step Fourier approach 1 implemented in a Python solver. 18 We address three models: 2D þ 1T with no contribution from ponderomotive force by solving Eq. ( 3), 1D þ 1T with no contribution from ponderomotive force by solving Eq.…”