Automated laser damage test system with real-time damage event imaging and detection

An automated laser damage test system has been developed by the National Ignition Facility small optics metrology group. The Small Optics Laser Damage (SOLD) system measures the fluence at which laser damage occurs in optical coatings and substrates following the requirements of MEL01-013-OD. Irradiation of the sample is by a 1064nm, 8ns pulse with a 1mm 1/e(2) diameter. The test protocol requires raster scanning of a 1cm(2) area at increasing fluence levels. Real-time high-resolution imaging of the surface during raster scanning enables automated detection and sizing of defects to 10 microns. Improved imaging resolves actual size of damage events while the automated damage detection removes the subjectivity of the human operator in thresholding damage events. In addition, a map is created enabling additional functions such as excluding damage sites on future scans and to returning to the damage site for growth testing.