Temperature-dependent refractive index measurements of wafer-shaped InAs and InSb

An experimental method is introduced to measure the refractive index and its temperature dependence for wafer-shaped infrared materials over a continuous temperature range. Using a combination of Michelson interferometry, Fabry-Perot interferometry, and a temperature-controlled cryostat in a laser micrometer, refractive index values and their temperature coefficients can be measured for any specific temperature within a desired temperature range. Measurements are reported for InAs and InSb for a laser wavelength of 10.59 microm.