Thermal lens effect and laser characteristics of Ho:YAG ceramic laser with a concave-convex cavity

In this paper, the thermal lens effect of dual-end-pumped Ho:YAG ceramic laser was studied experimentally and numerically. The thermal lens magnitude of Ho:YAG ceramic was obtained by beam quality inverse method. When the pump power increased from 9 to 88 W and the according pump radius increased from 0.2 to 0.25 mm, the thermal focal lengths in X and Y directions were decreased from 102 to 65 mm and 140 to 68 mm, respectively. Considering of the thermal lens, we further optimized the laser resonator with a concave-convex cavity and the slope efficiency was increased by 11.6 percent compared to the plane-concave cavity.