Antireflective sub-wavelength structures on fused silica via self-assembly of silica

Abstract

Antireflective sub-wavelength structures with high laser-induced damage threshold on fused silica are fabricated using a self-assembly technique, in which a porous yttrium oxide film is deposited as a mask followed by alkaline etching. By controlling the etching time, several sub-wavelength structures with different height, density and diameter have been made. The best reflectance is less than 2.87% for wavelengths from 300 to 1000nm after 1.5h etching. The laser-induced damage threshold of the etched glass measured by a 10ns Nd:YAG laser at a wavelength of 532nm was as high as 30J/cm2 compared to 16J/cm2 of blank glass. The specular reflectance of structures matches the theoretical simulation using a thin-film multilayer model, and the results reveal that the shape of the structures is similar to the calculated parabolic shape. Achieving antireflective sub-wavelength structures on fused silica paves the way for applications in laser systems.