Simple method for reducing the depolarization loss resulting from thermally induced birefringence in solid-state lasers

A simple technique for reducing the loss that is due to depolarization resulting from thermally induced stress birefringence in solid-state lasers is reported. The technique uses a single intracavity quarter-wave plate with its fast or slow axis aligned parallel to the preferred plane of polarization, defined by an intracavity polarizer. This technique has been applied to a diode-bar-pumped Nd:YAG laser operating at 946 nm, resulting in a measured reduction in depolarization loss from ~1.7% to ~0.0006% and yielding a diffraction-limited, TEM(00) , linearly polarized output power of 2.9 W for an incident pump power of 14.3 W.