All-dielectric nanoantennas

Abstract

The study of optical nanoantennas is a rapidly developing area of optics and nanophotonics. Nowdays, the most popular type of nanoantennas is a plasmonic one made of metallic elements. However, plasmonic nanoantennas have large dissipative losses. Here we present an overview of the recent results of a newly emerged field of all-dielectric optical nanoantennas. These optical nanoantennas are made of high-permittivity low-loss dielectric particles. Moreover, in addition to the electric resonances such nanoscale particles exhibit very strong magnetic response in the visible range. We introduce and study a highly efficient Huygens element and Yagi-Uda type nanoantennas based on dielectric nanoparticles. We also introduce a novel concept of all-dielectric superdirective nanoantennas based on the generation of higher-order optically-induced magnetic multipole modes. For such superdirective dielectric nanoantennas, we predict the effect of beam steering at the nanoscale characterized by a subwavelength sensitivity of the beam radiation direction to the source position. Based on all these new properties, optical nanoantennas offer unique opportunities for applications such as optical communications, photovoltaics, non-classical light emission, and sensing.