Tunable exciton polaritons in biased bilayer graphene

TL;DR

This paper demonstrates how bilayer graphene can be used to create electrically tunable exciton polaritons in a microcavity, with potential enhancement from epsilon-near-zero materials, advancing flexible optoelectronic applications.

Contribution

It introduces a novel platform for electrically tunable exciton polaritons in bilayer graphene within a microcavity, combining semiclassical and quantum approaches for analysis.

Findings

Strong exciton-photon coupling predicted under realistic conditions

Integration of epsilon-near-zero materials can enhance light-matter interaction

Polariton dispersions and Rabi splittings characterized

Abstract

By harnessing the unique properties of bilayer graphene, we present a flexible platform for achieving electrically tunable exciton polaritons within a microcavity. Using a semiclassical approach, we solve Maxwell's equations within the cavity, approximating the optical conductivity of bilayer graphene through its excitonic response as described by the Elliott formula. Transitioning to a quantum mechanical framework, we diagonalize the Hamiltonian governing excitons and cavity photons, revealing the resulting polariton dispersions, Hopfield coefficients and Rabi splittings. Our analysis predicts that, under realistic exciton lifetimes, the exciton-photon interaction reaches the strong coupling regime. Furthermore, we explore the integration of an epsilon-near-zero material within the cavity, demonstrating that such a configuration can further enhance the light-matter interaction.