Canalization of surface plasmon polaritons on a graphene sheet with a perturbed ground plane

Summary form only given. Canalization of surface plasmon polaritons (SPPs) on a layer of suspended graphene is investigated. In the canalization regime (Phys. Rev. B. vol. 71, pp. 193105, 2005), spatial harmonics propagate with the same phase velocity. One application of canalization is in sub-wavelength imaging to overcome the diffraction limit. It is shown that a graphene sheet with anisotropic conductivity can provide a canalization regime with the phase velocity of spatial harmonics being equal to the phase velocity in free space. The anisotropic conductivity is derived by tuning the isofrequency contours for SPPs. Similar to the layered perfect lens introduced in (J. Mod. Optics, vol. 50, pp. 1419-1430, 2003), a composite graphene sheet consisting of strips having complex conductivities with alternating positive and negative imaginary parts provides the anisotropic effective conductivity which is essential for canalization.