Passively Q-switched Ho:LuAG laser with near-diffraction-limited beam quality

A passively Q-switched Ho:LuAG laser resonantly pumped by a 1.91-mu m laser was presented. A comparison analysis of laser performances with two different output couplers was carried out. Using Cr2+:ZnS as the saturable absorber, the maximum average output power of 1.14 W was obtained at 2,076.56 nm. The pulse duration was kept constant while increasing the pump power. Meanwhile, the pulse energy is linearly dependent on pump power. The shortest pulse duration of similar to 36 ns and highest pulse energy of 1.54 mJ were obtained at output coupler transmittance of 25 and 30 %, corresponding to the pulse repetition rate of 554 and 790 Hz, respectively. The beam quality factor of M (2) was 1.05, which is the near diffraction limited.