Point defects induced at the exit surface of optical-grade fused silica by high power (>30J/cm2) 355nm laser pulses were investigated to elucidate the nature of laser damage in optics for use at high peak powers (>2GW/cm2). Six defects were identified. Eγ’ and E74’ defects were identified by using electron spin resonance spectroscopy. The non-bridging O hole center, a self-trapped exciton, an O-deficient center, and interstitial O2 were identified and spatially resolved in the damage craters by using cathodoluminescence microanalysis. The defects were associated with the laser generated shock waves and/or thermal explosion.

Defects Induced in Fused Silica by High Fluence Ultraviolet Laser Pulses at 355nm. M.A.Stevens-Kalceff, A.Stesmans, J.Wong: Applied Physics Letters, 2002, 80[5], 758-60