title: Strong coupling of surface plasmon polaritons in monolayer graphene sheet arrays.
abstract: Here we investigate theoretically and numerically the coupling between surface plasmon polaritons (SPPs) in monolayer graphene sheet arrays that have a period much smaller than the wavelength. We show that when the collective SPP is excited with an out-of-phase illumination, the beam tends to propagate toward the opposite direction of the Bloch momentum, reflecting a negative coupling between the constituent SPPs. In contrast, for in-phase illumination, the incident beam is split into two collective SPPs that are highly collimated and display low propagation loss. Moreover, the coupling between the individual SPPs results in a reduction of the modal wavelength of the SPP in comparison with that of a single graphene sheet.
authors.affiliation: Institute of Materials Research and Engineering, Agency for Science, Technology, and Research, Singapore. wangb@imre.a-star.edu.sg
authors.forename: Bing
authors.initials: B
authors.lastname: Wang
authors.forename: Xiang
authors.initials: X
authors.lastname: Zhang
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: García-Vidal
authors.forename: Xiaocong
authors.initials: X
authors.lastname: Yuan
authors.forename: Jinghua
authors.initials: J
authors.lastname: Teng