利用传播圆图解方法,分析了非对称平直腔固体激光器的热透镜效应对激光器的动力学稳定区的宽度、基模光斑尺寸和发散角的影响。此方法避免了传统ABCD矩阵法所需的繁琐计算,结果清晰明了,进而给出了测量晶体热焦距的一个简单方法。在该理论的指导下,设计了符合试验条件的谐振腔参量,并进行了实验研究,测量了激光二极管端面抽运的Nd:YVO4激光器的热焦距和光斑模式,当抽运功率23 W时获得了稳定的10 W准基模连续输出,实验结果与理论符合得很好。

The influence of thermal lens on the width of dynamic stabilization, angle of divergence and output mode of solid-state laser with asymmetry flat-flat cavity was analyzed by using transition circles theory. Compared with the ABCD matrix method which need a large number of computations, this method was relatively simple and the result was easily understood. Moreover a simple method to measure the length of thermal focus is given developed from this theory. By properly designing the parameters of resonant cavity, steady 10 W quasi-TM 00 mode CW output was achieved when the pumped power was 21 W. The mode and length of thermal focus of laser were measured. The experimental result was in accordance with theory.