Transverse-Electric Surface Plasmon in Graphene Under Uniform Strain

Abstract

Compared to surface plasmon polariton in metals, graphene can support transverse electric (TE) surface modes when the imaginary part of its conductivity is negative. TE graphene plasmons are generally weakly confined in direction perpendicular to the graphene plane, and they cannot be resonantly excited by an external incident wave because their dispersion curve spectrally lies just below the light line. In this work, we investigate theoretically the light reflectance of a graphene layer under uniform strain on the top of a one-dimensional photonic crystal consisting of high and low-index dielectric materials and a material film layer on the graphene sheet. The strain not only changes the electronic band structure but also can be employed to influence the electronic collective excitations and thus the optical reflectance of graphene monolayers. We demonstrate that TE plasmon excitation is based on the observation of a pronounced sharp minimum in the reflection coefficient of the suggested photonic structure upon the incident angle, the wavelength, and refractive index. Therefore, the graphene under uniform strain on the photonic structure is found to be promising in the fabrication of optical sensors devices with TE plasmons.