An acoustic-optically Q-switched Tm:SSO laser at 2 μm

An actively Q-switched Tm:SSO laser was realized by using an acoustic-optical (AO) modulator, and stable Q-switching operation was obtained with the pulse repetition frequency (PRF) varying from 1 kHz to 10 kHz. At PRF of 1 kHz, the Tm:SSO laser yielded a shortest 308 ns pulse with M2 factor less than 1.6 at 1968 nm, corresponding to a single pulse energy of 128 μJ and pulse peak power of 416 W. The experimental results indicate the Tm:SSO crystal is favorable for obtaining low PRF 2 μm laser pulses.