A bimetallic nanoantenna for directional colour routing

TLDR

Recent advances in nanophotonics have demonstrated meta‑materials with negative refraction, directional single‑photon sources, plasmonic analogues of electromagnetically induced transparency, and Fano resonances, all largely governed by a single optical‑phase parameter. The authors present a nanophotonic structure comprising closely spaced gold and silver disks that accumulate phase through material‑dependent plasmon resonances. This bimetallic dimer can be fabricated wafer‑scale and allows manipulation of optical response via polarization, material choice, and geometry, providing a versatile platform for practical applications. The compact dimers exhibit directional scattering of red and blue light in opposite directions, achieving exotic optical properties in a structure only ∼λ/100 in size.

Abstract

Recent progress in nanophotonics includes demonstrations of meta-materials displaying negative refraction at optical frequencies, directional single photon sources, plasmonic analogies of electromagnetically induced transparency and spectacular Fano resonances. The physics behind these intriguing effects is to a large extent governed by the same single parameter-optical phase. Here we describe a nanophotonic structure built from pairs of closely spaced gold and silver disks that show phase accumulation through material-dependent plasmon resonances. The bimetallic dimers show exotic optical properties, in particular scattering of red and blue light in opposite directions, in spite of being as compact as ∼λ(3)/100. These spectral and spatial photon-sorting nanodevices can be fabricated on a wafer scale and offer a versatile platform for manipulating optical response through polarization, choice of materials and geometrical parameters, thereby opening possibilities for a wide range of practical applications.