Modeling a polarization-bistable neodymium laser with a Cr{sup}4+: YAG passive switch under the weak resonant radiation control

摘要

Previously we reported the experimental observation [1] and theoretical simulation [2] of the drastic dependence of the state of polarisation of a neodymium laser passively Q-switched with a Cr{sup}4+:YAG crystal (see Fig. 1,a) on relative orientations in the laser cavity of the passive switch (PS) and an partial polariser (PP). It has been shown that polarisation state of the laser is governed both by relative orientations of the Cr{sup}4+:YAG PS and of the intracavity PP as well as by the energy density of a giant pulse (GP) in the switch. Complicate behavior of the polarisation state is due to an "interplay" between the PP action (which causes the linear anisotropy of the cavity) and that of the Cr{sup}4+:YAG crystal (which causes the nonlinear anisotropy of the cavity). In particular, when the cavity parameters are chosen by a suitable manner, one should observe sharp, by 90{deg}, jumps of the GP polarisation azimuth, while only slight (～1{deg}) azimutal tuning of the Cr{sup}4+:YAG crystal about the cavity axis takes place.