Pump Spectral Linewidth-Dependent Competition and Dynamic Behaviors of Stimulated Brillouin-, Raman-, and Kerr-Scattering in Carbon Disulfide

In this paper, we present systematical results of pump spectral linewidth dependence of the threshold, energy conversion (nonlinear reflectivity), dynamic behavior, and spectral structure of backward stimulated Brillouin-, Raman-, and Kerr-scattering in CS₂ liquid pumped by 532-nm and nanosecond-pulsed laser beams, with three largely different spectral linewidths. First, under a super-narrow linewidth (≤0.01 cm^-1) pump condition, stimulated Brillouin scattering (SBS) is the only predominant process that could provide a higher (≥30%) nonlinear reflectivity. Second, under a narrow line (0.07 cm^-1) linewidth pump condition, stimulated Kerr scattering (SKS) is the dominant process, accompanied by a much weaker SBS contribution, but the overall nonlinear reflectivity is drastically reduced to ≤1%. Third, under a moderate (0.8 cm^-1) linewidth pump condition, SKS is the only process to be observed. The self-termination phenomenon of SKS process has been found, it is caused by the thermal self-defocusing effect due to Stokes-shift energy conversion, and this effect severely restricts the efficiency of SKS generation.