888 nm laser diode end-pumped continuous wave and passively Q-switched Ho:YAG laser

• The 2.1 μm Ho:YAG laser pumped by an 888 nm laser diode is first reported. • The output performances of continuous wave laser are demonstrated. • With the Cr:ZnS saturable absorber , the output characteristics of Q-switched laser. A 2.1 μm Ho:YAG laser directly pumped by an 888 nm laser diode was demonstrated for the first time, to the best of our knowledge. The output performances of continuous wave and passively Q-switched Ho:YAG laser were investigated at the different output coupler transmittances. For the continuous wave operation, the maximum output power of 396 mW was obtained at the absorbed pump power of 3.7 W, corresponding to the slope efficiency of 22.6 %. For the passively Q-switching operation, the maximum average output power was 103.2 mW at the absorbed pump power of 3.7 W, with a pulse width of 62.9 ns and a repetition frequency of 1.105 kHz. The experiment results show that the 888 nm laser diode is a promising pump source to achieve 2.1 μm laser output in Ho:YAG crystal.