采用基于半导体可饱和吸收镜的被动调Q微晶片激光器, 对三通掠入射Nd∶YVO4板条激光放大器进行了实验研究。理论研究了水平方向模式匹配比和掠入射角对板条激光放大器热致畸变的影响。实验验证了掠入射板条激光放大器水平方向最优模式匹配比为0.6, 且采用较小的掠入射角可以在保证高增益的同时产生较小的水平方向热致畸变。确定模式匹配比为0.6且三通掠入射角分别为3°、5°、7°时, 重复频率为100 kHz、平均功率为2 mW、光束质量因子M2=1.17的种子光源所产生的激光经过掠入射Nd∶YVO4板条三通放大后, 最终获得12.6 W的激光输出, 光-光提取效率达到28%, 脉冲峰值功率为1.1 MW, 脉冲能量为126 μJ, M2=1.4。

A experimental study about a triple-pass grazing incidence Nd∶YVO4 slab laser amplifier is carried out based on a semiconductor saturable absorber and passively Q-switched microchip lasers. Influences of the mode matching ratio in horizontal direction and grazing incidence angle on thermal distortion of slab laser amplifier are analyzed theoretically. The experiment verifies that the mode matching ratio of the grazing incident slab laser amplifier in horizontal direction is optimized to be 0.6. Meanwhile, with a small grazing incidence angle, thermal distortion in horizontal direction can be alleviated and high gain can be obtained. When the repetition rate is 100 kHz and the seed source is with an average power of 2 mW and a seed beam quality factor M2 of 1.17, a laser output of 12.6 W can be obtained after triple-pass amplification of grazing incidence Nd∶YVO4 slab with a mode matching ratio of 0.6 and a triple-pass grazing incident angles of 3°, 5° and 7°, respectively. The optical-optical extraction efficiency reaches 28%. The peak pulse power is 1.4 MW, the pulse energy is 126 μJ, and M2 is 1.4.