为了提高固体激光器的热稳定性和光斑质量,讨论了LD泵浦三镜折叠腔绿光激光器的热焦距与泵浦功率、激光晶体长度、泵浦光发散角以及泵浦光聚焦位置的关系。利用谐振腔内往返传输矩阵算法,计算了在不同热焦距下,腔内元件不同长度时,其上的基模半径,理论上很好地实现了输出光斑的像散补偿。在532nm绿光实验中,以Nd∶YVO4为增益介质,5mm和10mm KTP为倍频晶体,获得较好的光斑质量和较高的光-光转换效率,最高达17.8%。

In order to improve thermal stabilization and beam quality, the relation between thermal focal length and pump power, the length of laser crystal, pump beam divergence, focus position for pump beam are discussed. For different thermal focal length, the round-way transmission matrix to calculate the fundamental mode radius on components with different length are used , and astigmatic compensation in theory are achieved. On the experiment, using Nd∶YVO4 as the laser crystal, 5mm and 10mm KTP as the frequency doubling crystal, we obtain laser beam of high quality and high optical-optical conversion efficiency which can reached to 17.8% at most.