Optical reflector coatings for astronomical applications from EUV to IR

Optical coatings are an integral part of superior optical components. Astronomical applications (ground- and space-based) place especially high demands on these coatings, not only with regard to their optical performance but also to their mechanical and environmental stability, their thermal properties, and their radiation resistance. This article presents a short overview of several coating solutions developed in recent years at Fraunhofer IOF in order to meet the challenging demands of astronomical applications. The focus is placed on high reflective coatings for different wavelength regions including coatings for the VUV range below 100nm, coatings for the DUV wavelength range above 100nm and VIS/NIR/IR coatings. Further, amorphous silicon layers will be introduced which can be polished to very low roughness values and therefore can act as polishing layer for the manufacture of ultraprecise optical components from metal substrates.