Cryogenic refractive indices of ZnSe, Ge, and Si at 10.6 microm

Refractive-indexm easurementsa s a function of temperature have been made for zinc selenide, germanium, and silicon at 10.6 jlm over a temperature range of 20-300 K. Each measurement was made by finding the deviation angle of a beam perpendicularly incident on a right triangle prism. The curves for index of refraction versus temperature have been fitted to polynomials, and values for the change in index with temperature are given as a function of temperature.