在平凹临界稳定腔脉冲式Nd:YAG激光器中插入LiF:F-2晶体实现稳定锁模运转。分析LiF:F-2非线性吸收在锁模过程中的作用，计算Nd:YAG自聚焦引起的腔的稳区范围和激光振荡模式的变化。理论和实验结果均表明，克尔透镜效应是实现该激光器锁模运转的关键因素。

The stable mode-lockingoperation of a pulsed Nd:YAG laser was achieved by inserting a LiF:F-2 crystal into the critical stableplane-concave resonator. This paper analyzed the action of nonlinear absorption of LiF:F-2 inmode-locking progress, and calculated the changes of stable range of the resonator and thelaser mode sizes, due to self-focus of Nd:YAG. The theoretical and experimental results showed that the Kerrlens effect was the key factor of mode-locking operation for the Nd:YAG laser.