Temperature-dependent dispersion fitting for a recent infrared glass catalog

Optical design requires an accurate knowledge of the dispersion functions for the materials in each lens. For systems to work over a wide range of temperature, knowing the temperature dependence of these functions is as important as knowing the coefficients of thermal expansion. The dispersion curves of several NRL-developed infrared glasses were measured over a temperature range that spanned, at minimum, -20 degrees C to 60 degrees C. Room temperature data were fit to a Herzberger model, and the temperature dependence treated using the same model used by Schott Glass, Inc. The final results are saved in a form compatible for import using Zemax OpticStudio.