▎ 摘　　要

By using monolayer graphene as saturable absorber, a passively Q-switched Tm:LuAG laser with high efficiency at 2 mu m is demonstrated. At the incident pump power of 5.8 W, pulses with duration of 235 ns and maximum average output power of 873 mW were obtained at a repetition rate of 72 kHz. This is, to the best of our knowledge, the highest average output power, as well as the narrowest pulse width, ever obtained among graphene-based passively Q-switched solid-state bulk lasers at 2 mu m regime.