Metal mirrors are an attractive solution for scan mirrors working with ultra-short pulse lasers. Small mechanical inertia and a small mirror mass are required. Therefore, the mirrors have to be very stiff and a high quality optical surface has to be provided. This can be achieved with lightweight AlSi based mirrors with diamond-turned NiP polishable plating.

Different coating options were evaluated in order to provide the necessary high reflectivity and a satisfactory laser damage threshold for ultrashort laser pulses in the few ps to fs regime at λ = 1030 nm. High-reflective metal layers enhanced by dielectric HfO₂/SiO₂ stacks were found to be the most advantageous coating option due to their comparatively small thickness and measured damage thresholds above 1 J/cm²@8ps.

Date Published: 12 March 2015
PDF: 11 pages
Proc. SPIE 9351, Laser-based Micro- and Nanoprocessing IX, 93510S (12 March 2015); doi: 10.1117/12.2079487

Published in SPIE Proceedings Vol. 9351:
Laser-based Micro- and Nanoprocessing IX
Udo Klotzbach; Kunihiko Washio; Craig B. Arnold, Editor(s)