Pump Side-scattering in Ultra-powerful Backward Raman Amplifiers
Extremely large laser power might be obtained by compressing laser pulses through backward Raman 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.
- Research Organization:
- Princeton Plasma Physics Laboratory, Princeton, NJ (US)
- Sponsoring Organization:
- USDOE Office of Science (SC) (US)
- DOE Contract Number:
- AC02-76CH03073
- OSTI ID:
- 827678
- Report Number(s):
- PPPL-3928; TRN: US0403666
- Resource Relation:
- Other Information: PBD: 2 Mar 2004
- Country of Publication:
- United States
- Language:
- English
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