Locking of transverse modes in a Raman laser

A theoretical analysis is made of the characteristic features of the excitation of the stimulated Raman scattering by a monochromatic beam in a plane-parallel optical resonator. It is shown that in this case the transverse Stokes modes are locked. The nature of the locking is governed, generally speaking, by the amplitude-phase distribution of the pumping radiation over the input mirror of the resonator and not by the intensity of this radiation. The possibility of generation of a single transverse amplitude-phase distribution of the pumping radiation field is considered. The examples of two- and three-mode resonators are used to illustrate the method for finding the distribution of the pumping field necessary for the excitation of a single transverse Stokes mode.