Measurement of Birefringence in Nonlinear Crystals by Michelson Interferometer

We present a method to measure the index of refraction of a wafer-type material accurately by using a modified Michelson interferometer. With this method, the difference between the refractive index of the ordinary-wave and that of the extraordinary-wave in the representative nonlinear crystal, LiNbO
₃
could be measured with ease.