Interferometric determination of the birefringence dispersion of anisotropic materials

A channelled spectrum resulting from two-beam interference fringes is formed by illuminating an anisotropic material, placed between two crossed polarizers in front of a spectrograph, with a parallel beam of white light. The resulting interferogram is analyzed by a simple approach to deduce the birefringence and its dispersion across the visible spectrum. A Cauchy and a fourth-order polynomial dispersion formula are used to fit the experimental data for a mica sheet and a transparency film. The method is simple, direct and accurate for deducing the birefringence of anisotropic materials and its dispersion. (C) 1997 Elsevier Science B.V.