Evaluation of metal mirrors for high power applications by multithreshold damage analysis

Development of damage-resistant mirrors for high power, pulsed infrared laser applications depends on accurate identification of dominant failure modes and their origin. Previous work indicates that metal surfaces are usually subject to plastic deformation, pitting, or Other effects which may degrade reflective properties long before laser-induced melting occurs. Here we examine file relationship between mirror preparation and thresholds for the various types of damage. Surface finishing methods such as polishing, precision diamond-turning and sputter-cleaning in ultrahigh vacuum are evaluated. Examples of different materials, fabrication methods, and the effects of oxidation and contamination are also included.