为了改善高能固体激光器由于激光增益介质的热畸变限制了激光器在大能量输出时保持高光束质量的能力, 提出一种基于离轴混合腔的高能双板条热容激光器, 并进行了实验研究。实验结果表明该激光器的双板条结构, 具有对温度分布不均匀造成的激光波面畸变实现部分自校正的能力。再配合离轴混合腔的使用, 可大大提高激光器的光束质量。实验中采用了两块尺寸为100 mm×20 mm×500 mm的大尺寸钕玻璃板条, 激光器的阈值泵浦电压大约是2 400 V左右, 斜效率为3.4%。当泵浦电压为3 400 V时, 激光器的输出脉冲能量达到158.07 J。泵浦电压为2 800 V时, 分别对近场和远场的光斑进行测量, 可计算得到非稳腔和稳腔方向的发散角分别为1.245 9 mrad和1.545 9 mrad。

In high energy solid-state lasers, the thermal induced distortion in laser gain medium limits the scalability of high energy output with high beam quality. In order to improve this problem a dual-slabs heat capacity laser with an off-axis hybrid resonator is presented and studied experimentally. The experimental results show that the thermal distortion of wave front caused by the non-uniform temperature distribution of the laser gain media slab will be self-corrected in this structure. The beam quality is greatly improved by using the off-axis hybrid resonator. The Nd:glass size is 100 mm×20 mm×500 mm. The threshold pumping voltage is 2 400 V, and the slope efficiency is 3.4%. 158.07 J pulse energy is obtained with 3 400 V pumping voltage level. By measuring the size of the output beam at near-field and far field respectively, the divergence is calculated to be 1.245 9 mrad in the unstable direction and 1.545 9 mrad in the stable direction.