Fluorides of some s-, p-, d-, and f-metals as prospective materials for interference optics: Present status and development

Materials with low refractive indices based on fluorides of some s-, p-, d- and f-metals for interference optics were examined. Issues concerned with the enhancement of both optical and operational properties of the thin-film coatings based on fluorides were discussed. A doping mechanism for REF3 (RE – Sc, La–Lu) dopants in the widely used material – magnesium fluoride – was proposed. Interaction in the metal fluoride systems was established. The influence of the initial material composition on the structure and properties of coatings was determined.