A Narrow Linewidth Continuous Wave Ho:YAG Laser Pumped by a Tm:YLF Laser

A narrow linewidth cw Ho:YAG laser pumped by a 1908 nm Tm:YLF laser based on the volume Bragg grating is established. The maximum output power of 9.6 W for the incident pump power of 16.9 W is obtained, and the corresponding slope efficiency and optical-to-optical conversion efficiency are 67.2% and 56.8%, respectively. The Ho:YAG laser operates stably at 2122.1 nm by using two Fabry–Perot etalons, with a full width at half maximum less than 0.2 nm.