Short-Pulse Mid-Infrared Laser Based on SnSe2 Saturable Absorber

We propose a 2 μm Tm: YAP passively Q-switched solid-state laser based on SnSe₂ saturable absorber. With increase in the pump power, the output power of the laser can reach 430 mW corresponding to a shortest pulse width of 810.7 ns, a maximum repetition frequency of 59.55 kHz, a single pulse energy of 7.22 μJ, and a peak power of 8.9 W. The beam quality factor M²_x is measured successfully to be 1.43 under the maximum output power. This is the first time that a pulse width of 810.7 ns is achieved in a solid-state laser, using a Tm: YAP crystal and SnSe₂ as the saturation absorber.