Microchip laser operating at 1338 nm

Q-switched microchip laser emitting radiation at wavelength 1338 nm was designed and realized. This laser was based on monolith crystal which combines in one piece a cooling undoped part (undoped YAG crystal, 4 mm long), active laser part (YAG crystal doped with Nd3+ ions, 12 mm long) and saturable absorber (YAG crystal doped with V3+ ions, 0.7 mm long). The diameter of the diffusion bounded monolith was 5 mm. The initial transmission of the V:YAG part was 85 %. The microchip resonator consists of dielectric mirrors directly deposited on the monolith surfaces. The pump mirror (HT for pump radiation, HR for generated radiation) was placed on the undoped YAG part. The output coupler with reflection 90 % for the generated wavelength was placed on the V3+-doped part. Q-switched microchip laser was tested under pulsed, and CW diode pumping. The pulse length it was the same for all regimes equal to 6.2 ns. The wavelength of linearly polarized laser emission was fixed to 1338 nm. The pulse energy depends on the mean pump power. For pulsed pumping the output pulse energy was stable up to mean pump power 1 W and it was equal to 135 μJ, which corresponds to peak power 22 kW. In CW regime for pumping up to 14 W the pulse energy was stabilized to 37 μJ (peak power 6 kW). The mean output power increased up to 0.4 W only by increase of the generated pulse repetition rate (11 kHz for mean pump power 14 W).