Correlation of laser-induced damage to phase objects in bulk fused silica

The Optical Sciences Laser (OSL) Upgrade facility, described in last year's proceedings, is a kJ-class, large aperture (100cm2) laser system that can accommodate prototype optical components for large-scale inertial confinement fusion lasers. High-energy operation of such lasers is often limited by damage to the optical components. Recent experiments on the OSL Upgrade facility using fused silica components at 4 J/cm2 (351-nm, 3-ns) have created output surface and bulk damage sites that have been correlated to phase objects in the bulk of the material. Optical Path Difference (OPD) measurements of the phase defects indicate the probability of laser-induced damage is strongly dependent on OPD.