Laser damage investigations of Cu mirrors

Laser tests were performed on Cu mirrors as “first mirror” prototypes for laser diagnostics. Data on laser damage thresholds of surfaces under the influence of pulsed YAG laser radiation were obtained for single shot and after about 1.5 × 105 shots. The experiments were carried out using three types of copper mirrors: diamond-turned mirror, diamond-turned substrate with copper coating and reflection grating on a copper coated mirror. fetime of the copper mirrors was tested. Diffusion scattering was used as a monitor of mirror surface quality. The degradation of diamond turned copper mirrors in multiple pulse laser irradiation appears to be in satisfactory accordance with a model for multipulse laser damage of metal mirrors up to 1.5 × 105 laser pulses. The degradation of copper coated mirrors has a more complicated behaviour.