2π steering of surface plasmon polaritons with silicon nanoantennas

Abstract

We experimentally demonstrate full-angle control over the direction of excitation of surface plasmon polaritons on thin gold film with a single silicon nanosphere. Upon oblique excitation of the nanosphere with circularly polarized light beam, the directivity pattern of the excited surface waves exhibits rapid wavelength-dependent steering, which is the result of combined action of chiral response of the nanoantenna driven by mutual interference of its magnetic and electric dipole moments and chirality of the incident wave.