Holmium laser in-band pumped by a thulium laser in the same host of YAlO₃

We report on the room-temperature continuous-wave (CW) operation of a Ho:YAlO₃ laser that is resonantly end pumped at 1.94 μm by a diode-pumped thulium-doped laser in the same host. Through the use of a 1 at % Ho³⁺-doped 20-mm-long YAlO₃ crystal (b cut), the Ho:YAlO₃ laser generated 1 W of linearly polarized (E//c) output at 2118 nm and 0.55 W of E//a output at 2128.5 nm for an incident pump power of 5 W, with an output coupler transmission of 14 and 3%, respectively. An optical-to-optical conversion efficiency of 20% and a slope efficiency of 33% were achieved at 2118 nm corresponding to an incident pump power.