TEMPERATURE-DEPENDENCE OF ABSORPTANCE IN LASER DAMAGE OF METALLIC MIRRORS .1. MELTING

Damage thresholds for ultraclean metals are considered. An exact premelting temperature result for the case of optical absorptance A equals A//i plus A//lT//s is obtained which indicates that the surface-temperature rise T//s reduces the theoretical threshold (It//p)//m for raising T//s to the melting temperature T//m by a factor of 3. 6 to 1. 6, typically. Raising T//s to T//m is a good damage criterion for 100-ns pulses, but not for single subnanosecond pulses. The effect of pulse shapes is considered.