Photonic density of states enhancement in finite graphene multilayers

TL;DR

This paper demonstrates that finite graphene multilayers can significantly enhance photonic density of states and Purcell factors in the THz and mid-IR ranges due to coupled plasmon modes, with potential applications in nanophotonics.

Contribution

It reveals that few-layer graphene/dielectric stacks act as hyperbolic metamaterials with enhanced optical properties, expanding the understanding of their plasmonic behavior.

Findings

Enhanced Purcell factors in graphene multilayers.

Increased photonic density-of-states in THz and mid-IR.

Coupled plasmon modes drive the optical enhancements.

Abstract

We consider the optical properties of finite systems composed of a series of graphene sheets separated by thin dielectric layers. Because these systems respond as conductors to electric fields in the plane of the graphene sheets and as insulators to perpendicular electric fields, they can be expected to have properties similar to those of hyperbolic metamaterials. We show that under typical experimental conditions graphene/dielectric multilayers have enhanced Purcell factors, and enhanced photonic densities-of-states in both the THz and mid-IR frequency range. These behaviors can be traced to the coupled plasmon modes of the multi-layer graphene system. We show that these results can be obtained with just a few layers of graphene.