Refractive Indices of Rutile and Sphalerite

TLDR

Prisms made from single crystals of rutile and sphalerite were used to measure refractive indices across the visible spectrum and up to 1.5 µm, producing dispersion curves and their equations. The measured values agree moderately with published data, confirming rutile’s high dispersion, large birefringence, and strong violet‑end absorption that accounts for its slight yellow color.

Abstract

Prisms were made from single crystals of rutile and sphalerite and used in measuring the refractive indices of these materials. The measurements were made through the visible spectrum and extended to 1.5 microns in the infrared by the use of an infrared sensitive screen.The dispersion curves and the equations for the curves were determined. Values taken from the curves were found to agree moderately well with published values. The results demonstrate the high dispersion and the large birefringence of rutile. The experimental results also demonstrate the strong absorption of rutile in the violet end of the visible spectrum which accounts for the slight yellow color of rutile.