This paper describes automated pulsed testing of infrared mirrors based on scatter-probe detection of laser damage. Advantages of our approach are (1) ability to monitor minute changes in surface condition without an observer, (2) rapid sampling of a large matrix of test fluences and test positions on the mirror, (3) automatic selection of test fluences, (4) automatic control of laser intensity drift, and (5) compatibility with a vacuum test environment.

Automated determination of damage frequencies and relative damage onsets will be described for single-layer-coated and uncoated metal and semiconductor mirrors. Tests were performed at 2.7 and 10.6 μm with 1/e² focal spot diameters of 150 and 240 μm, respectively, using a nominal 100-ns pulse length in all cases. Results obtained with the scatter probe will be compared with those obtained from Nomarski postdamage analysis.