Energy characteristics of stimulated scattering of ultrashort light pulses

An investigation was made of the energy characteristics of stimulated Raman scattering (STRS) and of stimulated scattering in the Rayleigh wing (STSRW) of YAG laser pulses of 25 psec duration in benzene, carbon disulfide, and toluene. It was established that when the active-layer thickness was of the order of the spatial length of the laser pulses, the forward and backward STRS and STSRW processes were in the form of an amplified spontaneous noise of intensity which varied stochastically from one shot to another. The STRS and STSRW thresholds were governed by the relaxation times of the molecules in the active medium. When the thickness of the scattering layer was much greater than the spatial length of the laser pulses, the nature of the energy dependence of the forward STRS approached the energy dependence of the STRS excited by pulses of nanosecond duration.