Space radiation testing of thin film and multilayer optical coatings

Abstract

With the increasing complexity of optical designs flown on satellites, specialty thin film and multilayer filter coatings are being implemented more often. Unfortunately, very little ionizing radiation testing has actually been performed on such coatings, and certainly not completed to very high doses as might be experienced by an unshielded space optic in orbit for many years. In this paper we present results of gamma irradiation testing on the transmission properties of selected multilayer filters and optical coatings performed in an inert argon environment.

The effect of time on optical coating mechanical loss and implications for LIGO-India

“…More broadly, mechanical loss of dielectric coatings has not been tested for any possible degradation over time (perhaps due to water absorption or other contamination) and concerns have been raised about the effect on thermal noise of storing coated optics for many years. Prior research on long term degradation of dielectric optical coatings has primarily focused on space environments [22,23]. We investigated the effect of storing the coatings by measuring the mechanical loss of two coated silica disks, first measured in 2002 [12].…”