Index of refraction measurement on sapphire at low temperatures and visible wavelengths

Appl Opt. 1993 May 1;32(13):2224-34. doi: 10.1364/AO.32.002224.

Abstract

The ordinary and extraordinary refractive index of two samples of sapphire, which differed in the way each was grown, was measured. The measurements were made over a wavelength range of 477-701 nm and a temperature range of 20-295 K. A three-term Sellmeier dispersion equation was fit to the data to permit refractive-index interpolation within several parts in 10(4). The data of index versus temperature were fit to a model and the results of dn/dT versus temperature are given along with certain physical constants that were extracted from the model.