Perspectives for gapped bilayer graphene polaritonics

TL;DR

This paper explores the potential of gapped bilayer graphene for polaritonics, demonstrating that strong and ultrastrong light-matter coupling regimes are achievable, paving the way for advanced mid-infrared quantum technologies.

Contribution

It introduces the study of exciton-polaritons in tunable gapped bilayer graphene, showing their suitability for strong coupling regimes in quantum photonics.

Findings

Strong and ultrastrong coupling regimes are experimentally accessible.

Bound excitons dominate the optical response near the bandgap.

Potential for mid-infrared quantum polaritonics with tunable electronic properties.

Abstract

Bilayer graphene is normally a semimetal with parabolic dispersion, but a tunable bandgap up to few hundreds meV can be opened by breaking the symmetry between the layers through an external potential. Ab-initio calculations show that the optical response around the bandgap is strongly dominated by bound excitons, whose characteristics and selection rules differ from the usual excitons found in semiconductor quantum wells. In this work we study the physics of those excitons resonantly coupled to a photonic microcavity, assessing the possibility to reach the strong and the ultrastrong coupling regimes of light-matter interaction. We discover that both regimes are experimentally accessible, thus opening the way for a most promising technological platform, combining mid-infrared quantum polaritonics with the tunability and electronic features of graphene bilayers.