Self-oscillations in a cavity bounded by a sodium-vapor phase-conjugate mirror pumped by two cross-polarized beams

Abstract
We have observed self-oscillation in a linear cavity bounded by a sodium-vapor phase-conjugate mirror pumped by two cross-polarized beams. The oscillating beam polarization is analyzed along the directions of the pump polarizations, and different intensities are observed. The introduction of a quarter-wave plate inside the cavity permits the oscillation threshold to be lowered.