Spectral splitting of stimulated Raman scattering

An investigation was made of the spectral distribution of the components of stimulated Raman scattering (STRS) of light in liquid nitrogen, calcite, carbon disulfide, and nitrobenzene when the exciting radiation intensity was varied. It was found that the theory of the line narrowing on passage through a nonlinear medium failed to describe the spectral distribution of the first Stokes component of STRS. Near saturation the spectral distribution of the STRS components was almost equidistant. A hypothesis of noise origin of these components was put forward. A comparison was made of the observed spectral distributions with the spontaneous Gaussian noise spectra. The experimentally observed spectra were found to be highly regular and this was attributed to nonlinear transformation of light scattered as a result of the spontaneous Raman effect in the amplifying medium.