非稳腔中调腔孔对光束质量的影响

Influence of an alignment hole on the beam quality of unstable resonator

在中、远红外波段的激光器中，组成谐振腔的反射镜基底材料多数是对可见光不透明的，采用在腔镜上开一小孔输入调腔光方法是最简便的。本文用Ｆｏｘ－Ｌｉ迭代法计算了无开孔及有开孔时正支非稳共焦腔空腔的模式，结果表明当调腔光开孔直径小于３ｍｍ时，对光束质量基本没有影响。

In the middle and far infrared laser ,the cavity reflectors are not transparent to the visiblelight. A small hole is usually opened on one reflector to input a visible laser beam for alignment. Theeigenmodes of an unstable confocal resonator are calculated with and without a hole on the reflector.The beam quality affected by the small hole is discussed in the bare resonator and source resonator. It isindicated that the influence of the alignment hole on the beam quality can be ignored when the diameterof the hole is smaller than 3mm.