针对热容激光器的热透镜效应,给出了棒状钕玻璃热容激光器的热透镜公式表达式。理论上分析了热透镜焦距自平衡补偿方法的基本原理。在考虑了棒状钕玻璃热容激光器的具体特性的基础上,设计了一种简单的热透镜焦距自平衡补偿方法,使光抽运钕玻璃热容激光器在热透镜焦距变化情况下,可以使激光输出光斑大小稳定。为了解棒状热容激光器热透镜焦距的影响,利用自研的光栅型曲率传感器测量了热容激光器总的热透镜等效焦距的大小,结果表明热传导在抽运光发射完20 s左右后才建立热平衡产生了明显的热透镜效应; 随着抽运脉冲个数的增加,热透镜效应随之变大。

Under the study on rod Nd-glasses heat-capacity laser thermal lensing,the general expressions of the thermal focus length are derived. The self-adjusting compensation is presented in theory. Using the characteristic of Nd-glasses, self-adjusting compensation system for thermal lens focus is designed to weaken the effect of the thermal lens on light pumping glasses heat-capacity lasers. Thus, a stable output spot radius can be achieved while the thermal lens focus varies in a broad range. In order to study the effect of heat-capacity laser thermal lensing, a wavefront curvature sensor comprising a phase defocus grating is used to measure the focus length. The result indicates that the heat exchange sets up a heat balance in about 20 s after pumping. With the increases of the numbers of pumping pulses, the thermal focus length deceases.