Laser-Induced Damage Detection and Assessment by Enhanced Surface Scattering

A photoelectric damage detection and assessment system based on laser-induced changes in surface scattering is reported. The system is similar to one reported by Franck, et. al., with improved operating flexibility. It is integrated with a 1064/532 nm damage test facility used for routine testing of production optics. For some types of coated samples, a plot of scatter change vs. applied fluence can be extrapolated to the threshold fluence for surface pitting, eliminating the need for tedious microscopic assessment of near-threshold test sites. The system permits quantitative assessment of surface quality (by forward scatter) at a test site just prior to exposure by the damaging beam. thus, correlations between surface scatter and damage susceptibility may be investigated directly.