We explore the optical properties of a coaxial plasmonic metamaterial consisting of hollow dielectric cylinders with a diameter of 100-250 nm and a ring wall width of 10-50 nm, embedded in metal. We investigate the modal electric and magnetic fields and dispersion relation for different geometries and material choices of a single coaxial channel by using realistic values for all design parameters. The Fabry-Perot modes of a finite thickness slab are investigated with cathodoluminescence spectroscopy and explained by extracting the mode index from FDTD simulations. Furthermore, we investigate the coupling behavior of adjacent coaxes inside a hexagonal array. We find a change from the single-ring dispersion relation for coaxes with a ring-to-ring distance smaller than 20 nm.

New J. Phys.
Photonic Materials

van de Haar, M., Maas, R. C., Brenny, B., & Polman, A. (2016). Surface plasmon polariton modes in coaxial metal-dielectric-metal waveguides. New J. Phys., 18(Article number: 043016), 1–13. doi:10.1088/1367-2630/18/4/043016