Diode pumped passively Q-switched Nd:YAG/Cr:YAG solid-state lasers with a stable output of millijoules at 1064 nm over a wide temperature range

Passively Q-switched solid-state laser is potentially a very advantageous light source for automotive LiDAR application. The key challenge is the ability of wide temperature range operation. In this work we investigated high-power diode laser bar pumped passively Q-switched Nd:YAG/Cr:YAG solid-state laser with a stable output over a wide temperature range. Firstly we studied the impact of the pump light wavelength and the laser crystal temperature on the pulse energy and threshold, and results showed that to obtain the stable output of a solid-state laser in a wide temperature range, both the diode output and the laser crystal temperature should be stabilized in a reasonable small range. Further we designed and fabricated solid-state laser modules with a single active temperature control for both laser diode and crystal, which had stable pulse energy of millijoules with a pulse width of about 2 ns and a repetition rate of 30 Hz over a wide temperature range from -30 oC to 90 oC.