High average power passively Q-switched Yb:YAG micro-laser

We demonstrate operation of a compact, passively Q-switched Yb:YAG laser producing 10W average power at 1030nm in an 8.5kHz train of 1.2mJ, 1.6ns pulses. The laser is cw end-pumped with a fiber-coupled wavelength-stabilized 940nm diode. The pump light from the 105m diameter (0.1 NA) pigtail is collimated using a short focal length lens and directed into a 3mm long, 1mm thick 10 at.% Yb:YAG crystal. The saturable absorber is a Cr4+:YAG crystal with 76% unsaturated transmission. The laser’s slope efficiency is 52% and the optical-to-optical conversion efficiency is 33% at a pump power of 30W.