Stimulated Raman scattering subject to nonlinear effects

A model is developed for the description of stimulated Raman scattering. This model allows for changes in the level populations due to radiative transitions and it can be used also for an arbitrary detuning of the pump radiation from the center of a line of an atom in the active medium. A study is made of the conversion of wide-band laser radiation into a Stokes signal. It is shown that this conversion is quite efficient and the Stokes signal gain corresponds to coherent scattering. This result is related to the matching of the phases of the pump and Stokes signals. Numerical investigations carried out using this model under the experimental conditions described elsewhere give results in agreement with the experimental data.