Optical properties of complex fluoride films obtained using vacuum electron-beam evaporation

The ever-growing demands on the functional and operational characteristics of optical thin-film coatings have motivated studies on the properties of films formed using new film-forming materials, including complex fluorides. Interest in such materials is particularly due to the need for coatings with low refractive indices and low optical losses within a wide spectral region. In this paper, we studied the optical properties (refractive indices n and extinction coefficients k) of films formed from complex fluorides, namely, BaY2F8, CaY2F8, SrY2F8, and MgBaF4, which were obtained by the vacuum electron-beam evaporation method. The properties of these films were compared with the properties of films formed from simple fluorides, namely, BaF2, CaF2, SrF2, YF3, and MgF2, which were obtained under the same evaporation conditions. (C) 2020 Optical Society of America