Low-dimensional gap plasmons for enhanced light-graphene interactions

TL;DR

This paper introduces low-dimensional graphene gap plasmon waves that significantly enhance light-graphene interactions, enabling better field confinement and tunability for advanced plasmonic devices.

Contribution

It proposes a novel low-dimensional gap plasmon mode in graphene inspired by noble metal gap plasmons, improving field confinement and tunability.

Findings

Gap plasmon waves show superior field concentration compared to edge plasmons.

Adjusting graphene's chemical properties enables efficient mode modulation.

The approach offers potential for highly tunable graphene plasmonic devices.

Abstract

Graphene plasmonics has become a highlighted research area due to the outstanding properties of deep-subwavelength plasmon excitation, long relaxation time, and electro-optical tunability. Although the giant conductivity of a graphene layer enables the low-dimensional confinement of light, the atomic scale of the layer thickness is severely mismatched with optical mode sizes, which impedes the efficient tuning of graphene plasmon modes from the degraded light-graphene overlap. Inspired by gap plasmon modes in noble metals, here we propose low-dimensional graphene gap plasmon waves for large light-graphene overlap factor. We show that gap plasmon waves exhibit superior in-plane and out-of-plane field concentrations on graphene compared to those of edge or wire-like graphene plasmons. By adjusting the chemical property of the graphene layer, efficient and linear modulation of graphene gap plasmon modes is also achieved. Our results provide potential opportunities to low-dimensional graphene plasmonic devices with strong tunability.