Refractive index dispersion prediction for garnets (A₃B₂C₃X₁₂)

Abstract

A model for the refractive index dispersion of garnets was developed by extension of a model for garnet refractive indices at 589 nm wavelength. The cation and anion polarizabilities in garnets were determined as a function of wavelength from dispersion data, and fit to Sellmeier relations. Dispersion predictions were compared to measurements of refractive index between 400 and 5500 nm for 35 garnet compositions. The median prediction error was 0.5% with a maximum error < 4.4%. Sources of error and applications of the predictive method are discussed.