Laser-Induced Defects in a Bulk GaAs Used as an Output Coupler in an Nd？:？YAG Laser Cavity

By using bulk GaAs as an output coupler as well as a saturable absorber, with changing of concentration of defects inside the laser cavity, Q-switching of flashlamp-pumped Nd : YAG laser has been studied. It is shown that the formation of the laser pulses, in a wide range of duration, which were reported in a lot of previous papers is caused by the intracavity changes of the defect concentration in GaAs. The factor of increase in defect concentration is estimated by modeling of the pulse formation process.