Thermal-compensated high-stability, high-repetition-rate electro-optic Q-switched Nd:YAG laser and its application in MIR generation.

In this paper, a high-stability, high-pulse-energy 1064 nm electro-optic (EO) Q-switched laser at a repetition rate of 1 kHz has been demonstrated. The thermal lensing of composite Nd:YAG crystal was theoretically analyzed based on the simulation of the temperature distribution process. A thermally-compensated flat-convex laser cavity was developed to increase laser mode volume. The maximum single pulse energy of 9.1 mJ with a pulse width of 11.4 ns was achieved under the average pump power of 40 W, corresponding to the peak power of 0.8 MW and the slope efficiency of up to 40.4%. Besides, the pulse timing jitter was less than 600 ps, and the energy fluctuation in 40 minutes was about 0.09%. Based on a BaGaSe optical parametric oscillator (BGSe-OPO), the average power of 564 mW with a pulse width of 9.8 ns was achieved at 3.88 µm. Moreover, a wide tuning range of 3.0-5.04 µm was obtained by crystal angle tuning method. This compact laser system is a promising laser source for remote sensing and jamming.