Determination of Refractive Index of Thin Films from Interference-Fringe Reflection Spectra.

摘要

Reflection spectra were recorded on selected thin film materials from 2.5micrometers to 17.0micrometers using light polarized parallel to the plane of incidence. The materials were CdS,CdSe,CdTe,Ge,ZnS,ZnSe,and ZnTe vacuum evaporated onto KCl substrates. The spectra were analyzed using two different techniques: (1) The Fresnel reflection coefficients were applied to a three media model,where the second medium had an extinction coefficient,and (2) an index of refraction was computed from the interference fringes of the spectra. The interference-fringe analysis indicates that the index of refraction of the thin film coatings is approximately the same as that of the bulk material in the 10.0micrometer region,except for CdS. (Author)