报道了一种利用球差补偿效应提高侧面泵浦主振荡功率放大器输出光束质量的实验装置。在理论上提出了一种新的球差补偿方法,利用正球差经过会聚透镜焦点后向负球差转化的现象,补偿下一放大级中的正球差效应。在实验上搭建了两级放大的侧面泵浦Nd:YAG主振荡功率放大器。在连续输出的情况下,从振荡级输出功率为42 W、光束质量因子为1.48的种子光,经过一级放大后的功率为74 W,光束质量因子恶化为1.80;继续经过二级放大后,光束质量因子提高为1.40。实验结果表明,所提出的球差补偿理论是提高激光放大过程中光束质量的有效手段。

The beam quality enhancement in a side-pumped master oscillator power amplifier is experimentally realized by a novel method of spherical aberration compensation. Numerical calculations show that the positive spherical aberration is reversed to a negative one after the beam focus; in addition, the negative spherical aberration can be compensated by another amplifier. A two-stage side-pumped Nd:YAG master oscillator power amplifier has been developed. Seed beam from the oscillator with 42 W CW output power and a beam quality of 1.48 has been boosted up to 74 W after the first amplifier, with a degraded beam quality of 1.80. As expected, the output beam quality has been enhanced to 1.40 after the second amplifier. The experimental results verify the validity of the method to improve the beam quality in the process of laser amplification.