Enhanced optical transmission apparatus with improved aperture geometry

Abstract

An apparatus for enhanced light transmission is provided. The apparatus comprises a metal film having a first surface and a second surface, at least one aperture being provided in the metal film and extending from the first surface to the second surface. The at least one aperture comprises an entrance portion disposed on the first surface of the metal film and an exit portion disposed in the second surface of the metal film, each portion having a cross-sectional area in the plane of the corresponding metal film surface, wherein the cross-sectional area of the entrance portion is not equal to the cross-sectional area of the exit portion. A periodic surface topography is provided on at least one of the first and second surfaces of the metal film, the periodic surface topography comprising a plurality of surface features, wherein the geometry of each aperture entrance portion substantially matches the geometry of the surface features.

Dependencies are inferred from the claim text.