Nd:YAG/V:YAG monolithic microchip laser operating at 1.3 μm

Two longitudinally diode-pumped Nd:YAG/V:YAG Q-switched microchip lasers emitting radiation at wavelength 1.3 μm were realized. The first laser, designed for higher pump power, was based on the composite crystal which combines in one piece a 4 mm long cooling undoped YAG crystal, 12 mm long Nd:YAG laser active part, and 0.7 mm long V:YAG saturable absorber. The second one was designed to obtain shorter pulse length. It consists of 4 mm long Nd:YAG crystal and 0.7 mm long V:YAG crystal. The initial transmission of the V:YAG part (85%) and the output coupler reflectivity (90%) was the same in both cases. The generated pulse length was independent on pumping power for both crystals. For longer (shorter) crystal it was equal to 6.2 ns (1.7 ns FWHM). The wavelength of linearly polarized TEM00 laser mode was fixed to 1338 nm for longer crystal. In case of shorter crystal instabilities were observed for higher pump power. The average pulse energy was equal to 37 μJ for longer crystal, and 15 μJ for shorter one.