The effect of water vapor on nanosecond laser damage resistance of optical coatings in vacuum

In this paper, the effects of water vapor on the laser-induced damage of e-beam evaporated dielectric anti-reflection coatings in vacuum were investigated. The laser-induced damage resistance of the samples was measured in 1-on-1 and R-on-1 mode in vacuum and water vapor atmosphere. The LIDT of the anti-reflection coatings in vacuum was improved after introducing water vapor. The effects of the oxygen vacancy defect and thermal conductivity and stress change were considered to explain the improved LIDT.