Observations of the morphology of laser‐induced damage in copper mirrors

The results of multiple‐pulse damage tests on copper mirrors using 1.7‐ns CO2 lasers are reported. The measured reduction in the brightness reflectivity of the mirrors is shown to be correlated to the dramatic appearance of fine scale microstructure on the mirror surface. Scanning electron micrographs of this surface structure are presented and possible explanations of the effects are discussed.