Optical properties of mixed yttria-silica films

The refractive indices and absorption coefficients of a series of mixed yttria-silica films prepared by electron beam codeposition have been calculated from transmission spectra. The dependence of the refractive index and film densification on composition suggests that porosity inherent in pure yttria films deposited by electron beam evaporation can be reduced by admixture with silica; however, the films show increased absorption which is attributed to oxygen deficiency. These effects are similar to those observed previously in mixed zirconia-silica films.