A Q-switched Ho:YAG spatial ring cavity laser with three corner cube prisms pumped by a 1908 nm fiber laser

We demonstrate a tri-corner cube Q-switched Ho:YAG spatial ring cavity laser, which was resonantly pumped by a 1908 nm fiber laser. The polarization state of the intracavity oscillating laser was adjusted by a half-wave plate, and a continuous s-polarized laser of 2.57 W at 2090.9 nm was obtained at a pump power of 18.5 W, corresponding to an optical-to-optical conversion efficiency of 13.9 % and a slope efficiency of 33.3 %. When the corner cube prism, which has the weakest anti-misalignment capability, was tilted vertically by 1° or horizontally by 0.92°, the laser could still output the laser. For Q-switched operation, the tri-corner cube Ho:YAG laser has a pulse energy of 9.86mJ and a pulse width of 178.8 ns at a repetition rate of 100 Hz. At the maximum output energy, the beam quality was M_x² = 1.3, M_y² = 1.2.