FDTD subcell graphene model beyond the thin-film approximation

TL;DR

This paper introduces a novel FDTD subcell technique for accurately modeling the optical properties of graphene, surpassing the thin-film approximation in both accuracy and efficiency, applicable to complex structures like graphene metamaterials.

Contribution

The paper presents a new subcell FDTD method that accurately accounts for graphene's surface conductivity, improving modeling of dispersive responses beyond the thin-film approximation.

Findings

The subcell technique matches analytical solutions for planar graphene.

It outperforms the thin-film FDTD approach in accuracy and efficiency.

Successful simulation of graphene strip-grating metamaterials.

Abstract

A subcell technique for calculation of optical properties of graphene with the finite-difference time-domain (FDTD) method is presented. The technique takes into account the surface conductivity of graphene which allows the correct calculation of its dispersive response for arbitrarily polarized incident waves interacting with the graphene.The developed technique is verified for a planar graphene sheet configuration against the exact analytical solution. Based on the same test case scenario, we also show that the subcell technique demonstrates a superior accuracy and numerical efficiency with respect to the widely used thin-film FDTD approach for modeling graphene. We further apply our technique to the simulations of a graphene metamaterial containing periodically spaced graphene strips (graphene strip-grating) and demonstrate good agreement with the available theoretical results.