Disordered antireflective subwavelength structures using Ag nanoparticles on fused silica windows

In this paper, we have demonstrated an effective method for fabricating disordered subwavelength structures (d-SWSs) on fused silica using thermal dewetted Ag nanoparticles at lower temperatures (<300°C) with a vacuum. Theoretically and experimentally, we investigate the effects of the film thickness, annealing temperature, and etching time on the antireflective properties of the d-SWS arrays. The measured data and calculated results obtained by rigorous coupled-wave analysis exhibit reasonably similar tendencies. For the sample with a 10-nm-thick Ag film, good optical transmission characteristics (on one side, T_ave ~ 95.6%) over a wide wavelength region of 500-1300 nm were obtained, and a maximum value of ~96% at a wavelength of 850 nm was also obtained. Furthermore, the d-SWSs exhibit excellent optical and thermal stability at high temperatures of 800°C and 1000°C compared to a conventional Ta₂O₅/SiO₂ multilayer coating.