Characterisation of sub-radiant modes of metasurfaces

Abstract

Metallic nanostructures can be utilised as optical antennas: devices to assist the conversion between localised (near-field) and propagating (far-field) light. Optical antennas possess sub-radiant modes which cannot be easily coupled to propagating fields and have the advantages of longer life-times and higher Q resonances. This project has involved the computational and experimental investigation of the properties of sub-radiant modes of various nanoantennas that form the basis of a metasurface. These modes were found to be excited by off-normally incident light with a specific polarisation or vector beams with radial or azimuthal polarisation. It was also shown through studies of the optic..