Thin-film optical function acquisition from experimental measurements of the reflectance and transmittance spectra: a case study

The determination of the spectral dependence of thin-film optical functions from experimental measurements of the optical response, performed on thin-film/substrate structures, represents a problem of general interest to the thin-film community. In this paper, we present details related to thin-film optical function acquisition from experimental measurements of the reflectance and transmittance spectra, these being worked out through a case study performed on the optical functions associated with a series of thin-films of silicon that had been grown through ultra-high vacuum evaporation deposition on optical-quality-fused quartz substrates, this study being performed by Moghaddam et al. (J Mater Sci: Mater Electron 31:13186–13198, 2020). Following the presentation of our approach to deposition, details related to our optical response measurements, the uncertainty in our reflectance and transmittance results, the analytical framework within which the optical functions were acquired, how the ambient and the optical-quality-fused quartz substrate optical functions were modeled, and means through which unphysical solutions were identified and eliminated, are presented. We believe that the collection of these results will be of interest to those within the broader thin-film community.