Abstract

High laser damage threshold mirrors for ultraviolet light are required for the next generation of inertial fusion lasers. These lasers place greater demands on the coatings in terms of fluence levels, optic size, and stability. We have investigated the effects of ion-assisted deposition on the laser damage threshold of high reflector coatings for 351-nm 0.7-ns pulses. The coating materials used were HfO₂, ZrO₂, and Y₂O₃ for the high refractive-index layers with SiO₂ and MgF₂ as the low refractive-index layers. Contamination effects from the ion source grids and filaments were found to have a significant impact on the damage threshold of the thin film device. Improvements in the coating thresholds occur after either continuous or intermittent ion bombardment with the appropriate parameters and ion source configuration.

© 1991 Optical Society of America