Design and top-down fabrication of metallic L-shape gap nanoantennas supporting plasmon-polariton modes

Abstract

In this work the design, fabrication and optical characterization of a polarization-sensitive L-shape nanoantenna device are reported. Such configuration supports plasmon-polariton modes that are combinations of in-phase and out-of-phase single antenna long-axis surface plasma oscillations. In the former case charges distributions induce in the gap region an intense hot spot while in the latter one a “zero-field spot” occurs in a plasmonic mode which can be referred to a non-zero dipolar momentum.