Doubly Q-switched Tm:YAP laser based on the Cr2+:ZnS crystal and electro-optical modulator

A doubly Q-switched Tm3+:YAlO3 (Tm:YAP) laser based on the Cr2+:ZnS saturable absorber (SA) and electrooptical modulator (EOM) is presented. The pulse duration of the doubly Q-switched lasers is shorter as compared to single actively and passively Q-switched operations. The shortest pulse duration of 17.3 ns with a repetition rate of 100 Hz was measured at the pump power of 12 W in the doubly Q-switched laser. The corresponding pulse peak power of 184.8 kW and the pulse energy of 3.2 mJ was obtained. The center wavelength of the doubly Q-switched operation was 1.94 mu m. The results demonstrate that Cr2+:ZnS is an excellent saturable absorber for 2 mu m Tm:YAP laser, and the doubly Q-switched operation can greatly narrow the Q-switched pulse width.