Light scattering by a medium with a spatially modulated optical conductivity: the case of graphene

TL;DR

This paper demonstrates that spatial modulation of optical conductivity in graphene enables excitation of surface plasmon-polaritons at normal incidence, significantly enhancing electromagnetic absorption.

Contribution

It introduces a novel mechanism for exciting surface plasmon-polaritons in graphene through spatial conductivity modulation, which was not previously demonstrated.

Findings

Surface plasmon-polaritons can be excited at normal incidence due to conductivity modulation.

Modulation can be achieved via strain fields or adsorbed molecules.

Enhanced electromagnetic absorption results from plasmon excitation.

Abstract

We describe light scattering from a graphene sheet having a modulated optical conductivity. We show that such modulation enables the excitation of surface plasmon-polaritons by an electromagnetic wave impinging at normal incidence. The resulting surface plasmon-polaritons are responsible for a substantial increase of electromagnetic radiation absorption by the graphene sheet. The origin of the modulation can be due either to a periodic strain field or to adatoms (or absorbed molecules) with a modulated adsorption profile.