WS(2 )Passively Q-switched Er:SrF2 Laser at similar to 3 mu m

A few-layer tungsten disulfide (WS2) nanosheet film on a YAG substrate was fabricated and used as saturable absorber in a passively Q-switched Er:SrF2 laser operating at 2.79 mu m. Under an absorbed power of 2.42 W, a stable Q-switched laser operation was realized with an average output power of 428 mW and a pulse duration of 679 ns at a repetition rate of 38 kHz, corresponding to a pulse energy of 11.26 mu J.