Perfect absorption and strong magnetic polaritons coupling of graphene-based silicon carbide grating cavity structures

A hybrid structure of graphene ribbons suspended on grooves of a periodic SiC grating is proposed. Magnetic polaritons in the SiC grating can couple with surface plasmons in graphene ribbons. The field distributions obtained from COMSOL simulation, in agreement with the prediction from a LC circuit model, strongly indicate that magnetic polaritons can be excited in the SiC grating. We find that the SiC grating cavity acts as a perfect reflector; plasmon standing waves can be established under a certain size of the SiC grating. These standing waves can be confirmed using a Fabry-Perot model. The Fermi energy of graphene, and height of the grating can control the plasmon standing waves. Moreover, we analyze how the strong coupling between localized magnetic polaritons in the SiC grating and surface plasmons in graphene ribbons leads to the Rabi splitting of the absorption peak and perfect absorption in the mid-infrared region using a coupled harmonic oscillator model. These findings may promote the development of optoelectronic devices based on hybrid structures and can pave the way for the hybridization of the two types of modes.