Temperature dispersion of refractive indices in semiconductors

The variations of refractive index with temperature, i.e., the thermo-optic coefficients (dn/dT), are analyzed critically by use of a physical model for some important semiconductors to find the refractive index at any operating temperature for any wavelength throughout the transmission region. This model is based on three physical parameters—the thermal-expansion coefficient and two optical band gaps, such as excitonic and isentropic that are lying in the UV region, instead of considering any empirical equations.