Polarization Dynamics of a Distributed-Feedback Dye Laser

The polarization dynamics of a dye-solution laser with light-induced distributed feedback (DFB) has been analyzed. A theoretical model of a DFB-laser, which makes it possible to calculate the dynamics of the lasing process for two orthogonally polarized modes, has been constructed. The influence of three main factors — rotational diffusion of dye molecules in solution, anisotropy of the saturation effect, and orientation of the electric vector of pumping beams with respect to the plane of their incidence — on the degree of polarization of output radiation has been investigated. Comparison of the calculated dependences with the results of experimental measurements has shown that the latter factor is of the greatest importance. It is shown that in this case, the degree of polarization of the output radiation of a DFB-laser can have a complex dynamics that does not correlate with the time behavior of the lasing pulse.