title: Highly reflecting aluminum-protected optical coatings for the vacuum-ultraviolet spectral range.
abstract: We discuss the approaches to preserve the high-reflectance aluminum mirror for the vacuum-ultraviolet spectral region. Single fluoride and oxide layers, a homogeneous multilayer, and hybrid multilayer solutions are put forward. Single fluoride and oxide materials have achieved reflectance above 90% at 193 nm. Multilayer capping can provide reflectance of 93.4% at 193 nm, and a hybrid multilayer of fluoride and oxide can achieve reflectance above 90% to 160 nm.
authors.affiliation: Fraunhofer-Institut für Angewandte Optik und Feinmechanik, Albert Einstein Strasse 7, Jena 07745, Germany. minghong.yang@iof.fraunhofer.de
authors.forename: Minghong
authors.initials: M
authors.lastname: Yang
authors.forename: Alexandre
authors.initials: A
authors.lastname: Gatto
authors.forename: Norbert
authors.initials: N
authors.lastname: Kaiser