In-Band Pumped High Power Ho:YAG Ceramic Laser by a Tm:YLF Laser

We demonstrate a high power Ho:YAG ceramic laser resonantly pumped by a Tm:YLF laser at 1908 nm. The lasing characteristics of a 1.0 at.% Ho³⁺-doped YAG ceramic are investigated and compared with different output couplers. By using an output coupler of 50% transmission and 100 mm radius of curvature, a 26.8 W continuous wave is obtained at 2091 nm, corresponding to a slope efficiency of 57.9% and an optical to optical efficiency of 55.8% with respect to the absorbed pump power.