Interaction of terahertz electromagnetic waves with periodic gratings of graphene micro- and nanoribbons

An original mathematical model of the interaction of terahertz (THz) electromagnetic waves with periodic gratings of graphene micro- and nanoribbons is based on the solution to the boundary-value problem of diffraction for the Maxwell equations with electrodynamic boundary conditions and material equations. The electrodynamic calculations of the transmission coefficients of the TEM wave versus frequency are performed for the 2D grating of graphene micro- and nanoribbons at several chemical potentials, grating periods, and geometrical sizes of ribbons. The results of the calculations show that the transmission spectrum exhibits a minimum in the THz range if the electric field of the wave is perpendicular to the graphene ribbons. The minimum is due to the plasmon resonance of the fundamental mode in graphene, and the absorption peaks at higher frequencies in the upper part of the THz range are related to the highorder plasmon modes.