用于调节高功率固体激光装置“神光Ⅱ”功率平衡的变角度衰减片会对光束产生影响，包括光轴的横向移动、光路的等效长度发生变化、附加光程及波面的弯曲等。通过变角度衰减片的光学传播矩阵定量地分析了这些影响，特别提到光路的等效长度与光程是不同的概念，需要分别考虑。同时联系变角度衰减片的实际应用情况进行了讨论。

The angular variable mirror (AVM) to be used to control the power balance of beams of “SHENGUANG Ⅱ” system will affect the light beams, including vertical displacement of optical axis, alteration of equivalent length of optical path, additional optical distance, and the curve of wave surface. By the optical matrix, the effects have been analyzed quantitativelly, and point out that equivalent length of optical path is the different concept from optical distance. The application of AVM in practice is discussed.