Two passively Q-switched Nd:YAG monolithic microchip laser devices were prepared by Nd:YAG and V:YAG
crystals diffusion bonding. Stable generation of nanosecond pulses at wavelength 1338nm was obtained. The first
laser, designed for higher mean pump and output power, was based on the monolith crystal which combines in
one piece a 4mm long cooling undoped YAG crystal, 12mm long active laser part (YAG crystal doped with Nd3+ ions), and 0.7mm long V3+:YAG saturable absorber. The second one was designed to obtain shorter pulse length.
It consists of 4mm long Nd:YAG laser crystal and 0.7mm long V3+:YAG saturable absorber. The diameter of
both crystals was 5 mm. The initial transmission of the V:YAG part (T0 = 85%) and the laser resonator was
the same in both crystals. Laser mirrors were deposited directly onto monolith faces. The output coupler with
reflection 90% for the generated wavelength was placed on the V3+-doped part. The pump mirror (HT@808 nm,
HR@1.3 μm) was placed on opposite monolith face. Both microchip lasers were tested under longitudinal diode
pumping. The pulse length was stable for all regimes for both crystals. For longer crystal it was equal to 6.2 ns,
for the shorter one it was 1.7 ns (FWHM). The wavelength of linearly polarized TEM00 laser mode was fixed
to 1338nm for longer crystal. In case of shorter crystal some instabilities were observed for higher mean pump
power. The pulse energy depends on the mean pump power. For pulsed pumping with low duty factor the output
pulse energy was equal to 131 μJ for longer crystal, and 34 μJ for shorter crystal. This corresponds to peak power
21kW and 20kW, respectively. In CW pump regime the pulse energy was 37 μJ for longer crystal (peak power
6 kW), and 16 μJ for shorter one (peak power 9.4 kW).