Optical constants of tin-telluride determined from infrared interference spectra

The simple variant of the envelope method to deduce the optical constants from interference extrema is extended to the back reflectivity case. The finite substrate thickness correction for the three types of measurement is included. The envelope method is applied to the experimental spectra of front and back reflectivities and transmittivity of an SnTe epitaxial layer. The errors in the determination of the optical constants are estimated. Our results suggest that we can obtain better information by using reflectivity data rather than transmittivity data.