Theory of magnetically controlled low-terahertz surface plasmon-polariton modes in graphene-dielectric structures

This paper investigates the electromagnetic behavior of transverse magnetic (TM) surface plasmon-polaritons guided by a magnetostatically biased, laterally infinite graphene surface at the interface between two dielectric materials. We present the theory for the reflectance calculation of a graphene-based attenuated total reflection (ATR) device, and analyze the conditions for the observation of surface polaritons in the 500 GHz-5 THz frequency range. In the absence of magnetostatic field B-0, TM surface excitations in graphene are generated only by TM-polarized incident waves. In the presence of B-0, the surface conductivity of graphene becomes a tensor, allowing surface polaritons to be excited by transverse electric (TE) polarized incident waves as well. Features in the ATR reflectance curves for TM- or TE-polarized incident radiation for several B-0 are identified as corresponding to TM surface waves for the range of frequency examined. It is observed that the surface excitations produced by TE incident light display stronger confinement than the surface polaritons excited by TM incident light. Knowledge of the electromagnetic properties of graphene-dielectric structures may be valuable for modern applications in the field of tunable plasmonic graphene electronics at the far-infrared. (C) 2015 Optical Society of America