High-energy, stable single-frequency Ho:YAG ceramic amplifier system

We demonstrate a 2090 nm single-frequency, high-energy, Q-switched Ho:YAG ceramic master oscillator and power amplifier system that contains two-stage amplifiers. The maximum single-frequency pulse energy is 55.64 mJ at a pulse repetition frequency of 200 Hz. The half-width of the pulse spectrum is measured to be 3.96 MHz by a heterodyne technique. To the best of our knowledge, 55.64 mJ is the highest single-frequency output energy obtained from the Ho:YAG laser.