Abstract

The direct nano-structuring of the surfaces of an optical element is nowadays a well-established technique used primarily to enhance the light transmission through that optical element. Typically periodic or quasi-periodic in nature, these anti-reflective surface structures (ARSS) can be designed to generate strong interference effects over large bandwidths [1,2], to work in various materials [3] and to exhibit additional characteristics such as high laser damage thresholds [4]. The period of the pattern should be on a sub-wavelength scale and the height of the individual features on the wavelength scale to avoid the undesired diffraction effects (as the period becomes close to the wavelength of interest) while providing the required phase change (or optical impedance matching between the air, in the typical case, and the optical element), respectively. Modeling of these structures is typically done using rigorous coupled-wave analysis RCWA methods although the effective-index method can also provide reasonable insight (it cannot however model through the diffraction edge region) [5]. We will present a review of our work on surface nanostructuring of many technologically important optical materials and components and illustrate record-low reflectivity losses, large bandwidth and record-high laser damage thresholds.

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