LD end-pumped Tm: YAG Q-switched laser with novel multi-pass gain configuration

An LD end-pumped Tm: YAG Q-switched laser with novel multi-pass gain configuration is reported for the first time. A quarter-wave plate and a 45-degree polarizer are inserted in the cavity to improve the gain of Tm: YAG laser. The output energy of 8.25 mJ, with a pulse width of 121.1 ns, is obtained from a Tm: YAG laser operating at a Q-switched repetition rate of 50 Hz under continuous-wave pumping. The central wavelength is 2014.17 nm. The beam quality is M-x(2) = 1.20, M-y(2) = 1.22.