Two layer graphene heterostructures for waves slowing down: operator approach to waveguide problem

Abstract

Slowing down the phase velocity of light in media has various applications. The generation of electromagnetic radiation using coherent Cherenkov mechanism is among them. Meanwhile, there is a need for compact terahertz radiation sources. Due to outstanding graphene properties, heterostructures consisting of alternating graphene/dielectric layers can operate as a medium for the generation of terahertz radiation. In the present paper, the slowing down and propagation coefficients for the modes supported in a two-layer graphene structure are studied. The study is conducted by means of the operator approach to wave propagation in stratified structures. The operator approach allows one to use coordinates-free notations and to consider consequently arbitrarily complex heterostructures (including anisotropic layers, for instance). The influence of interlayer distance and the value of graphene chemical potential on waves slowdown is determined. The obtained results open up prospects for creating a new type of terahertz radiation sources.