Plasmonic rod dimers as elementary planar chiral meta-atoms

TL;DR

This paper theoretically analyzes metallic rod dimers as elementary planar chiral meta-atoms, demonstrating their elliptical dichroism and potential for easier fabrication of planar chiral metamaterials.

Contribution

It introduces a simple geometric model for planar chiral metamaterials using rod dimers and provides analytical and numerical analysis of their directional asymmetry.

Findings

Rod dimers exhibit elliptical dichroism without in-plane symmetry.

Metamaterials based on these dimers are easier to fabricate than traditional structures.

Analytical and numerical methods confirm the dependence of asymmetry on dimer geometry.

Abstract

Electromagnetic response of metallic rod dimers is theoretically calculated for arbitrary planar arrangement of rods in the dimer. It is shown that dimers without an in-plane symmetry axis exhibit elliptical dichroism and act as "atoms" in planar chiral metamaterials. Due to a very simple geometry of the rod dimer, such planar metamaterials are much easier in fabrication than conventional split-ring or gammadion-type structures, and lend themselves to a simple analytical treatment based on coupled dipole model. Dependencies of metamaterial's directional asymmetry on the dimer's geometry are established analytically and confirmed in numerical simulations.