Abstract
Raman amplification in plasma has been proposed to be a promising method of amplifying short radiation pulses. Here, we investigate chirped pulse Raman amplification (CPRA) where the pump pulse is chirped and leads to spatiotemporal distributed gain, which exhibits superradiant scaling in the linear regime, usually associated with the nonlinear pump depletion and Compton amplification regimes. CPRA has the potential to serve as a high-efficiency high-fidelity amplifier/compressor stage.
Highlights
This limitation has led to the suggestion of the use of stimulated Raman backscattering in plasma as an alternative amplifying medium [5] because plasma can sustain very high fields
We present the first experimental investigation on the role of frequency chirp in the linear regime of Raman amplification in a preformed uniform plasma channel
To observe chirped pulse Raman amplification (CPRA), an experiment with two collinear counterpropagating beams in a plasma channel was set up using the terahertz to optical pulse source (TOPS) high-power laser system [23], which provides a 350 mJ, 170 ps chirped pump beam at λ0 = 800 nm with a spectral bandwidth λ ≈ 25 nm, at a chirp rate α = ω/ T ≈ 4.47 × 1023 s−2
Summary
This limitation has led to the suggestion of the use of stimulated Raman backscattering in plasma as an alternative amplifying medium [5] because plasma can sustain very high fields. In the linear regime, the intrinsically narrow bandwidth of the Raman instability, equal to 2γ0 [8], and its convective instability [10], lead to temporal stretching of the seed [6], reducing its usefulness as a shortpulse amplifier To avoid these limitations, Shvets and co-workers [6, 11, 12] have proposed taking advantage of the nonlinearity of the medium at high intensities to produce soliton-like ultra-short pulses through pump depletion or, at higher intensities, by operating in the Compton or superradiant [13] regime where the ponderomotive force exceeds that of the plasma wave, i.e. when the bounce frequency, ωB = 2ω0√a0a1, of plasma electrons in the ponderomotive well exceeds ωp [11, 12]. Such a dependence will occur with a monochromatic pump and a plasma with a density gradient [12]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
