Simple method for reducing the depolarisation loss due to thermally-induced birefringence in solid-state lasers

Abstract

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