Steering of Guided Light with Dielectric Nanoantennas

All-dielectric nanoantennas proved to be an extremely versatile tool for efficient light manipulation at the nanoscale. Their rich functionality and excellent performance arise due to low absorption and high refractive index of all-dielectric materials, in particular, silicon, which enables the observation of pronounced magnetic and electric Mie resonances in subwavelength structures in the visible and near-infrared ranges. Here, we demonstrate that all-dielectric spherical nanoantennas placed on a substrate supporting guided modes provide efficient control over their directivity pattern, achieved due to the interplay between polarization of the incident light and the interference of electric and magnetic dipole resonances of the nanoantenna. In particular, by managing only the wavelength and polarization state of the incident plane wave at a fixed direction of incidence, it is possible to implement highly directional full-angle steering of surface plasmon polariton on a gold film. As a proof of concept, we experimentally demonstrate plasmonic beam steering with a single silicon nanoantenna using circular polarization of light. Our approach offers unprecedented versatility for designing nanoscale antennas with applications in integrated nanophotonics and quantum optics.