Pump Side-scattering in Ultra-Powerful Backward Raman Amplifiers.

Solodov, A. A. ; Malkin, V. M. ; Fisch, N. J.

Technical Information Center Oak Ridge Tennessee

关键词: Lasers;    Laser pulses;    Plasmas (Physics);    Beams;    Pulses;   

RP-ID  :  DE2004827678

学科分类：工程和技术（综合）

美国|英语

来源: National Technical Reports Library

【 摘 要 】

Extremely large laser power might be obtained by compressing laser pulses through backward Ra- man amplification (BRA) in plasmas. Premature Raman backscattering of a laser pump by plasma noise might be suppressed by an appropriate detuning of the Raman resonance, even as the desired amplification of the seed persists with a high efficiency. In this paper we analyze side-scattering of laser pumps by plasma noise in backward Raman amplifiers. Though its growth rate is smaller than that of backscattering, the side-scattering can nevertheless be dangerous, because of a longer path of side- scattered pulses in plasmas and because of an angular dependence of the Raman resonance detuning. We show that side-scattering of laser pumps by plasma noise in BRA might be suppressed to a tolerable level at all angles by an appropriate combination of two detuning mechanisms associated with plasma density gradient and pump chirp.