Q-Switched Ho:YAG Laser Pumped by a Tm:Fiber Laser

The efficient Q-switched Ho:YAG hybrid laser resonantly pumped by a 15 W Tm: fiber laser of output power at the wavelength of 1908 nm was developed. The output power of 3.5 W CW for 10.2 W of incident pump power was reached at the wavelength of 2090.1 nm. In Q-switching regime an acousto-optic modulator was applied. In CW pumping regime the repetition rate was changed from 20 Hz to 5000 Hz. For the best one, for 20 Hz repetition rate, pulses of 2.5 mJ energy and 125 kW peak power were achieved. For the best case of Q-switching in quasi cw pumping regime (repetition rate of 20 Hz and pulse width of 8 ms) the pulses of 127 kW peak power (2.8 mJ, 22 ns) were obtained.