Development of high-power laser coatings

Abstract

Laser resistance and stress-free mirrors, windows, polarizers, and beam splitters up to 400 mm × 400 mm are required for the construction of the series SG facilities. In order to improve the coating quality, a program has been in place for the last ten years. For the small-Aperture pick-off mirror, the laser-induced damage threshold (LIDT) is above 60 J=cm2 (1064 nm, 3 ns), and the reflected wavefront is less than λ=4 . λ D 633 nm/. The Brewster-Angle polarizing beam splitter (φ50 × 10 mm) shows the best LIDT result, up to 29:8 J cm-2 (1064 nm, 10 ns) for a p-polarized wave in the 2012 damage competition of the XLIV Annual Boulder Damage Symposium. For the larger-Aperture mirror and polarizer, the LIDT is above 23 J cm-2 (1064 nm, 3 ns) and 14 J cm-2 (1064 nm, 3 ns), respectively. The reflected wavefront is less than λ=3 . λD 633 nm/ at the used angle. .