Synthesis of Adjacent Stokes Spectra in a Two-Stage Transient Stimulated Raman Chirped-Pulse Amplifier

Abstract

The synthesis of adjacent overlapped Stokes spectra in two stages of a transient stimulated Raman chirped-pulse amplifier, tuned respectively to the vibrational modes at 901 and 767 cm−1 of a potassium gadolinium tungstate [KGd(WO4)2] crystal, is demonstrated. The contribution of the spatio-temporal overlap of seed and pump pulses, as well as the self-phase modulation, was investigated. The noncollinear configuration allows the composite bandwidth at the central wavelength of 1120 nm to be increased by a factor of 23 compared to the pump pulse bandwidth of 1.6 nm. After reaching a conversion efficiency of 35% in the second stage, the compressibility of a chirped Stokes pulse with a tailored spectrum was also investigated.

KGW and YVO: two excellent nonlinear materials for high repetition rate infrared supercontinuum generation

“…The spectral modulation is associated with filament refocusing, which leads to secondary pulse splitting, and hence to the interference between the primary and secondary split sub-pulses. Note that in the femtosecond regime, no signal with a Stokes shift due to stimulated Raman scattering is detected, which is otherwise exploited for Raman frequency shifting, amplification, spectral broadening and subsequent compression of picosecond pulses [33][34][35]. The spectral dynamics as a function of the input pulse energy in YVO crystal is shown in Fig.…”