Forward and backward splitting angles of Wollaston prisms and their symmetry

In order to find out the forward and backward splitting angles of a Wollaston prism and their symmetry,satisfactory data were obtained by combining mathematical calculations and experimental test.Analysis shows that the main reason of the symmetry difference of the splitting angles is that the o light incident on the first prism becomes e light on the second prism and then does not parallel to the optical axis of the crystal,no longer is caused by the principal refractive indices.The results demonstrate that the splitting angles becomes slightly larger when it is used positively than negatively.Moreover,the wavelength gets more and more shorter as long as the angle of the prism's structure became larger.Besides,the difference value between forward and backward splitting angles will get larger too.