Dispersion of the Birefringence of Crystal Quartz, Magnesium Fluoride, and Synthetic Sapphire

Abstract

Accurate methods for characterizing birefringence are crucial for the design andproduction of optics that manipulate polarized light, especially for waveplates that require precise thickness to achieve a specific retardance at a given wavelength. Typically, the tolerances for polishing waveplates are approximately ± 0.25 μm. This thesis characterizes the birefringence of three commonly used waveplate materials: crystal quartz, magnesium fluoride, and synthetic sapphire and compares values of two independent experimental methods. Dispersion formulae for each material are established and verified against existing literature. The results indicate a high level of agreement between the two experimental methods, showing consistency within 1.0 × 10−5 for birefringence values across the wavelength range of 300-1800 nm. Furthermore, the experimental data align closely with the published values, with deviations within 1.0 × 10−5 for quartz and magnesium fluoride and within 3.0 × 10−5 for sapphire.