A study of BaxMg1 − xF2 optical films

Ba x Me 1 − x F 2 binary fluoride films (“Me” denotes calcium or magnesium fluoride) are studied. A method of processing the reflection and transmission spectra is proposed to determine the optical constants. The dispersion dependences of the refractive indices and absorption coefficients of films in the range of 1.3–12 μm are found. Dispersion in films in the regions of additional absorption bands, which are absent in single crystals, is observed for the first time. It is shown that the films of binary fluorides have a higher packing density, a lower absorption, and better operating characteristics than do films of pure fluorides. The films are promising for application as optical interference coatings in the mid-IR spectral region.