A compact passively Q-switched Tm-Ho codoped crystal laser at 2 µm with narrow pulse duration

Abstract A Tm,Ho:YVO4 laser with compact geometry was demonstrated and analyzed. For the continuous wave laser, the slope efficiency of 30.5% was achieved. By inserting a Cr:ZnS saturable absorber into the cavity, the passively Q-switched laser generated almost constant pulse duration of 83 ns with the slope efficiency of 19.3%. The pulse energy was also independent of the pump power, around 130μJ. Through increasing the pump power from 3.7 W to 8.1 W, the pulse repetition varied approximately linearly from 2.9 kHz to 6.8 kHz. The Q-switch efficiency of the PQS laser is up to 58% at the maximum pump power.