Nd:YAG/V:YAG microchip laser generating 1 ns long pulses at 1338 nm

Q-switched microchip laser emitting radiation at wavelength 1338nm was designed and constructed to obtain nanosecond laser pulses with multikilowatt peak power. This laser was based on a composite crystal which combines in one piece an active laser part (2mm long YAG crystal doped with Nd3+ ions 1.2 at.% Nd/Y) and a saturable absorber (0.6mm long V3+:YAG). The initial transmission of the V:YAG part was ~ 85%@1.34 μm. The diameter of the diffusion bounded monolith was 5 mm. The microchip resonator consists of dielectric mirrors directly deposited on the monolith surfaces. The pump mirror (HT for pump radiation @ 0.8 μm, HR for generated radiation @ 1.3 μm) was placed on the Nd:YAG part. The output coupler with reflection 90% @1.34 μm was placed on the V3+-doped part. To prevent a parasitic lasing at 1064 nm, the reflectivity of both this mirrors was minimized at this wavelength. The overall length of constructed microchip laser was 2.6 mm. Laser was tested under pulsed diode pumping (wavelength 808 nm, pulse length 300 μs, energy 5.1 mJ, repetition rate 25 Hz - 2 kHz). The generated pulse length was stable and it was equaled to 1.07 ± 0.02 ns. The wavelength of linearly polarized laser emission was 1338 nm. Up to the highest mean pumping power 10W, the output beam had well-defined Gaussian transversal profile with the half divergence angle not higher than 4 mrad. For the lowest pumping rep. rate, the generated pulse energy and peak power was 34 μJ and 33kW, respectively. For maximum pumping rep. rate the pulse peak power was 14kW.