Raman emission in an external resonator with nonlinear absorption at the Stokes frequency

An analysis is made of cw generation of the fundamental and first Stokes components of stimulated Raman emission in an optical resonator excited by an external monochromatic beam under conditions of efficient narrow-band nonlinear absorption at the Stokes frequency. Some features of this laser action are studied and a dependence of the oscillation intensity of the radiation field components on the exciting beam intensity is determined. It is found that nonlinear absorption substantially changes the character of the laser action in the system. In particular, it results in the establishment of a hysteretic dependence of the amplitudes of the radiation field oscillations on the pump wave amplitude, which may be of considerable practical interest. For example, these systems may be used as generators of tuned (Stokes) frequency rectangular pulses.