Impact of organic contamination on 1064 nm laser induced damage threshold of dielectric mirrors

The lifetime of optical components submitted to high laser fluences is degraded under organic contaminant enviromnent. The molecular background of the Ligne d'Integration Laser (LIL), prototype of the future Laser Megajoule, might reduce the laser damage threshold of exposed fused silica surfaces. This paper reports the interaction effects between pure model contaminant deposits and a pulsed 1064 nm laser radiation on the coming out of mirror damage. The experimental setup allowed us to condense nanolayers of model contaminants on optics, the deposit impacts were then investigated by Laser Induced Damage Threshold (LIDT) tests in Rasterscan mode. In order to highlight physical processes emphasizing the emergence of optics damage, we characterized the irradiated deposit using interferometric microscopy analysis and spectrophotometric analysis. The challenge was to determine physical and phenomenological processes occurring during the irradiation of a pure contaminant deposit with a 1064 nm pulsed laser and to study the impact of this model contaminant on the LIDT of dielectric SiO2/HfO2 mirrors.