Enhanced transmission beyond the cut-off through sub-Lambda Annular Aperture Arrays

Abstract

A cascaded structure of annular aperture arrays perforated in silver films is shown to act as a high quality Fabry-Pérot interferometer (quality factor up to 200). The transmission of a single nanostructured layer exhibits a cut-off wavelength beyond which there is no transmission. It is demonstrated, here, that the double structure permits to overcome this cut-off. It is also found that transmission is enhanced by a factor of 150 for certain wavelengths. This kind of cascaded nanostructured metallic layers offers many promising applications as well as for optical wavelengths than for THz-waves because this effect still exists for perfect metals. It opens up the path for the conception of a new generation of integrated components based on metallo-dielectric structures that can be easily tailored as tunable devices