Enhancement of Laser Damage Resistance at 1064 Nm of High and Anti-Reflective Optical Multilayers by Tailoring the Electric Field Distribution and Post-Annealing

Abstract

In this study, multilayer Ta2O5/SiO2 and HfO2/SiO2 films were deposited on glass substrates by ion beam sputtering and physical vapor deposition methods, respectively. The effect of electric field distribution and heat treatment of these oxide multilayers on laser damage resistance were investigated systematically. Optical performance was characterized by spectrophotometer. Electric field analysis and optic system design were performed by thin film design software. LIDT (laser-induced damage threshold) measurements were applied at 1064 nm to obtain laser damage values of optical coatings. Damage images were characterized by a Nomarski (with dark field type) microscope. It was observed that the LIDT value of HfO2/SiO2 anti-reflective optical films increases to 34 J/cm(2) when they are post-annealed at 350 degrees C. On the other hand, measured LIDTs as high as 26 J/cm(2) were achieved by tailoring the electric field distribution of high reflective coatings.