Femtosecond laser damage of a high reflecting mirror

Abstract Multiple pulse investigations of 130-fs Ti:sapphire laser-induced damage of a high reflecting mirror consisting of alternating λ/4-layers of Ta 2 O 5 and SiO 2 and a single 500-nm Ta 2 O 5 film were performed. In both cases, fused silica served as the substrate. For a fixed number of 1000 laser pulses per spot, a decrease in the damage threshold fluence of the mirror by a factor of two was observed by changing the repetition rate from 10 Hz to 1 kHz. A single 500-nm Ta 2 O 5 film shows higher damage resistance compared to the mirror. The mirror and the Ta 2 O 5 film samples were partially coated with a 300-nm-thick aluminium layer. The aluminium coating does not influence the damage threshold of the dielectrics underneath.