532-nm, nanosecond laser mirror thin film damage competition

Abstract

This year’s competition aimed to survey state-of-the-art visible high reflectors in the nanosecond pulse length regime. The requirements for the coatings were a minimum reflection of 99.5% at 0 degrees incidence angle light at 532-nm. The choice of coating materials, design, and deposition method were left to the participants. Laser damage testing was performed at a single testing facility using the raster scanning test protocol with a 6-ns pulse length laser system operating at 100 Hz in a single-longitudinal mode. A double blind test assured sample and submitter anonymity. The damage performance results (LIDT), sample rankings, details of the deposition processes, coating materials and substrate cleaning methods are shared. We found that hafnia/silica multilayer coatings deposited by all five deposition methods surveyed were the most damage resistant within their group under these test conditions. In addition, hafnia/alumina/silica designs deposited performed second best.