165-W cryogenically cooled Yb:YAG laser

Abstract

Thermo-optic distortions often limit the beam quality and power scaling of high-average-power lasers. Cryogenically cooled Yb:YAG is used to efficiently generate 165 W of near-diffraction-limited beam from a power oscillator with negligible thermo-optic effects. End pumped with 215 W of incident pump power from two diode modules, the laser has an optical–optical efficiency of 76%, a slope efficiency of 85%, and an M2 value of 1.02.