Intensity Dependent Absorption and Laser Induced Catastrophic Damage in Diamond Turned and Mechanically Polished Cu Mirrors at 1.06 μm Available to Purchase

Intensity dependent absorption and multiple pulse induced failure of mechanically polished and diamond turned Cu mirrors were investigated at 1.06 μm. A Q-switched single longitudinal and single transverse mode Nd:YAG laser operating at 10 Hz was the irradiation source in the experiments. Repetitively pulsed calorimetry was used to measure the absorption and to record the onset of the multiple pulse-induced failure at high intensities. The absorptance was found to increase with increasing intensity. The change was compared to that predicted by the Drude model where the increase in absorptance is related to temperature. A spot size dependence of the laser damage intensities was observed which is suggestive of the role of laser induced stresses in the failure process.