Enhancement of high reflectivity mirrors using the combination of standard and sculptured thin films

Abstract The total generated output power in high-power laser systems is mainly limited by the laser-induced damage phenomena in coated optics. A significant part of optics include high reflectivity coatings. A research was conducted for the development of advanced high reflectivity mirrors, capable to withstand extreme laser fluence and featuring spectral stability at different ambient conditions. A concept of combination of IBS and GLAD technologies was proposed and implemented to form a hybrid multilayer mirror for the 355 nm wavelength. An optical and structural properties were investigated to evaluate the advantages of both technologies. The relation between the number of sculptured silica layers and standard mirrors performance under the high power of laser radiation was determined. The results of analysis show an improved reflectivity and optical resistance of consolidated coatings. LIDT measurements indicate the potential of reaching 90 J/cm2 for 355 nm wavelength (pulse duration 2.5 ns) while maintaining the reflectivity value higher than 99.5%. New findings indicate the superiority of hybrid coatings if compared to both classical and all-silica coatings. This knowledge opens up the new possibilities in further development of extreme light sources.