W片的双折射

具有维格特效应的Ｗ片所显示的光学各向生中同时具备二向色性和双折射两个因素，两者均与波长有关，通常在双折射很微弱时予以忽略。本文提供了二向色性很强时双折射相当显著的实验结果，获得了一系列实验数据及曲线。本文还提供了一种同时测定一块Ｗ片的二向色性与双折射的原理及实验方法。

Birefraction of W Flat

In the W flat with Weigert effect, both dichroism and birefraction should be showed simultaneously, but the birefraction is neglected generally because of it′s small. In this paper, we give a experimental result showing a remarkable birefraction as the dichroism is very strong (the phase difference between extraordinary and ordinary light be able to 80° and the value of n e-n o～0.02). A series of data and curves of the experiment are obtained. A principle and experimental method for determining the dichroism and the birefraction of a W flat are suggestees.