Optical dot antenna and nanohole transmission

In this reported work, the authors optimised a dielectric dot as a radiator, studied its emission properties, verified the far-field pattern multiplication and obtained high directivity from the proposed dot antenna. Also the effect of the dot radiator on the extraordinary optical transmission (EOT) was studied through optically thick metal film with a periodic array of subwavelength apertures as well as a single circular aperture surrounded by finite periodic concentric annular grooves (bull´s eye). With dot radiators a high-intensity focused electric field beam and polarisation-independent EOT were obtained through periodic arrays of holes in metal film. Interestingly, the bull´s eye structure with an optimised dot radiator has transmission threefold larger and suppressed side lobes of the light beam emerging from it. These features might open a new pathway in the field of nanophotonics for multiple applications such as designing better near-field imaging devices, biosensors and improving the efficiency of solar cells etc.