Abstract

Two-channel spectroscopic polarization-modulation ellipsometry measurements have been made on four different glasses (a fused SiO₂ glass, a fine-annealed BK-7 glass, an indium-lead-phosphate glass, and a germanium-arsenic-selenium glass). It is shown that this technique is sensitive to thin surface layers and that these surface layers can be modeled by using the Bruggeman effective-medium theory with 50% glass and 50% voids. If we correct the experimental spectra for this surface layer, the refractive index of the sample can be determined to ±0.002 in the transparent region. For wavelength regions where the material is normally opaque, the ellipsometric data can be corrected for this overlayer, thereby increasing the accuracy of the determination of both the refractive index and the extinction coefficient.

© 1990 Optical Society of America