High-Power Passively Q-Switched Nd:YAG Laser at 1112 nm with a Cr4+:YAG Saturable Absorber**Supported by the Natural Science Foundation of Shandong Province under Grant Nos ZR2015FM018 and ZR2014FM028, and the National Natural Science Foundation of China under Grant No 61475086.

Abstract

A high-power passively Q-switched Nd:YAG laser operating at 1112 nm with Cr4+:YAG as a saturable absorber is demonstrated. Under 808 nm diode-direct pumping, the maximum average output power of 2.73 W is achieved at the pump power of 16.65 W, corresponding to an optical-to-optical conversion efficiency of 16.4%. At the same time, the pulse width, pulse repetition rate, single pulse energy and peak power are 27.2 ns, 9 kHz, 303.3 μJ and 11.2 kW, respectively. As far as we know, the result gives the highest average output power at 1112 nm generated by an 808 nm diode-end-pumped Nd:YAG laser.