Jesse A Frantz
US Naval Research Laboratory, USA
Title: Anti-reflection surface structures on optics as an alternative to thin fi lm antirefl ection coatings
Biography
Biography: Jesse A Frantz
Abstract
Anti-refl ection surface structures (ARSS) are nano-scale features patterned directly into an optical surface that are designed to have low optical refl ectance. Th ey have been demonstrated to increase the transmission of an optical surface to >99.9% and are an attractive alternative to traditional thin fi lm anti refl ection (AR) coatings for several reasons. They provide AR performance over a larger spectral and angular range and unlike thin fi lm AR coatings, they are patterned directly into the optic rather than deposited on its surface. As a result, they are not prone to delamination under thermal cycling that can occur with thin fi lm coatings and their laser damage thresholds can be considerably higher. In this presentation, we summarize results for ARSS on a variety of optical materials including silica, germanium, magnesium aluminate spinel and a variety of laser crystals. We discuss scale-up of the technique and describe results for ARSS with dimensions as large as 33 cm. We describe a surface modifi cation procedure that results in a superhydrophobic surface without a signifi cant decrease in transmittance. Finally, we show results for optical performance of ARSS on silica windows following sand and rain erosion testing showing that they are suitable for use in harsh environments.