Laser induced damage of multilayer coatings for 248 nm

Abstract

Antireflection coatings (AR), beam splitter coatings (BS) and high-reflectance coatings (HR) were prepared to study the effect of material properties and stack structures on the laser induced damage behaviors of coatings at a wavelength of 248 nm. All the coatings were deposited on fused silica substrates by electron beam reactive evaporation technique with the materials of aluminum oxide and silicon dioxide. Laser-induced damage thresholds (LIDTs), damage morphologies and profiles of damage sites of multilayer coatings were characterized to investigate the damage mechanism of coatings irradiated by the excimer laser. Besides, the temperature fields were calculated to better understand the damage mechanism with our programmed software. The results indicate that the absorption of defects and the electric field distribution of thin film greatly contribute to LIDTs of thin films.