对高功率腔内倍频激光器光束质量影响因素进行了初步分析, 提出了谐振腔优化设计、热效应补偿等改善光束质量的措施并进行了相应的实验研究。采用光束质量控制措施后, 在10 kHz重复频率下, 利用优质8 mm×8 mm×12 mm KTP晶体获得了63.7 W,M2≈9.65的高光束质量倍频绿光输出, 光-光转换效率达到9.7％; 在15 kHz重复频率下, 利用优质8 mm×8 mm×30 mm LBO晶体获得了79 W,M2≈6.46的高光束质量倍频绿光输出, 光-光转换效率达到9.8％。

Preliminary influence factor analysis of beam quality of high-average-power and high-beam-quality intracavity frequency doubled green laser is presented. The methods of improving beam quality such as optimal design of resonator cavity and compensation of thermal effects are described. The corresponding experimental research is done. With the control of beam quality, the green laser power of 63.7 W is obtained in a 8 mm×8 mm×12 mm KTP crystal with an M2 value of 9.65 and an optical-to-optical conversion efficiency of 9.7% at a pulse repetition rate of 10 kHz, and the green laser power of 79 W is generated in a 8 mm×8 mm×30 mm LBO crystal with an M2 value of 6.46 and an optical-to-optical conversion efficiency of 9.8% at a pulse repetition rate of 15 kHz.