Chaotic polarization behavior in a Raman laser

The study of Raman lasers, in which the gain required for lasing action is provided by a stimulated Raman process, has both theoretical and practical interest. Theoretically, for resonant-cavity excitation, a Raman laser is a mixed active/passive optical switching system. The pump excitation in the cavity is subject to a modified optical-bistability condition and is therefore a passive process; whereas the Raman lasing actively seeks its own frequency through adjusting its round-trip phase to a multiple of 2π. The cavity Raman lases only if this is possible within the allowed Raman detuning constraint. This combination of mutually interacting active and passive processes introduces fundamental new ideas in the study of optical switching processes. We have found that the laser suffers from dynamical instabilities which would appear to limit its usefulness for practical application. In this paper, we develop some of the background, and give illustrative results