Role of electron back action on photons in hybridizing double-layer graphene plasmons with localized photons

TL;DR

This paper explores how electron back action in double-layer graphene influences photon hybridization, leading to high-sensitivity optical tools and potential polariton condensation for threshold-free lasers.

Contribution

It introduces a formalism for graphene-plasmon hybridization that reveals new resonant features and their implications for sensing and laser applications.

Findings

High sensitivity to local environments beyond the diffraction limit.

Observation of triply-hybridized absorption peaks at high SP frequencies.

Potential for polariton condensation and threshold-free laser operation.

Abstract

Induced polarization by Dirac electrons in double-layer graphene can affect hybridization of radiative and evanescent fields. Electron back action appears as a localized optical field to modify an incident surface-plasmon-polariton (SPP) evanescent field. This leads to high sensitivity (beyond the diffraction limit) to local environments and provides a scrutiny tool for molecules or protein selectively bounded with carbon. A scattering matrix with frequencies around the surface-plasmon (SP) resonance supports this scrutiny tool and exhibits sensibly the increase, decrease and even a full suppression of the polarization field in the vicinity of a conducting surface for longer SPP wavelengthes. Moreover, triply-hybridized absorption peaks associated with SP, acoustic- and optical-like graphene plasmons become significant only at high SP frequencies, but are overshadowed by a round SPP peak for low SP frequencies. These resonant features (different from 3D photonic lattices) facilitate the polariton-only excitations, giving rise to possible polariton condensation for a threshold-free laser. The current graphene-plasmon hybridization formalism can be easily generalized to other two-dimensional materials, such as silicene, germanene, molybdenum disulfide, etc.