Determination of Optical Birefringence of S-Benzylisothiouronium Complex Crystals using Channelled Spectrum Method

The channeled spectrum method was used for measuring the birefringence of an anisotropic material. Crystals of uniform thickness were placed between crossed polarizers and illuminated with a tungsten source. The resulting pattern was analyzed to deduce the birefringence and its dispersion across the visible spectrum. Cauchy’s two parameter formula was applied to fit the experimental data. The Cauchy’s coefficients A and B were obtained by solving the linear equations using MATLAB. The value of birefringence was also calculated.