High-order stimulated Raman scattering in a highly transient regime driven by a pair of ultrashort pulses

Abstract

We demonstrate efficient generation of high-order anti-Stokes Raman sidebands in a highly transient regime, using a pair of approximately 100-fs laser pulses tuned to Raman resonance with vibrational transitions in methane or hydrogen. The use of this technique looks promising for efficient subfemtosecond pulse generation.

Four-Wave Optical Parametric Amplification in a Raman-Active Gas

“…Only the frequency modulation of the signal pulse by the nuclear response is observable as in Figure 5, and as observed in the previous reports [13][14][15][16]18,19,24,25]. The Raman resonant FWM [30][31][32][33][34][35] may also be employed for the FWOPA. The amplification in this case would be observable only at a specific signal wavelength determined by the Raman shift.…”

Cross-Correlation Frequency-Resolved Optical Gating for Test-Pulse Characterization Using a Self-Diffraction Signal of a Reference Pulse

“…The spacing of the beat is determined by the frequency separation of pulses A and B, not by the relative phase. This would not be the case for an ultrashort optical pulse synthesized using more than two discrete spectral components [26], for instance a pulse train synthesized using multicolor laser emissions generated via FWM [5][6][7]19]. The characterization of an optical beat formed by two-color laser beams is useful for the evaluation of the bandwidth available in the diagnostics.…”

“…Several approaches have been reported to date for their generation. One of the approaches, four-wave Raman mixing in a hydrogen gas, generates octave-spanning multicolor emissions in the optical region [5][6][7]. By Fourier synthesis of the multicolor emissions, intense sub-2-fs optical pulses can be generated.…”

Wideband pulse propagation: Single-field and multifield approaches to Raman interactions

“…Since in the experiments of [1,2,3,4,13] the emphasis was on a single Raman transition, a simple Bloch model is clearly appropriate, and indeed our approximations differ little from those of other theoretical approaches (such at that of HPB).…”

“…∼ 126THz), as in the transient-regime experiments of Sali et.al. [4,7]. In these experiments, typical pulses might be 70fs and 250fs wide at 800nm (30µJ) and 600nm (120µJ) respectively, and the comb of Raman sidebands generated are narrow and well separated.…”