Broadband two-dimensional hyperbolic metasurface for on-chip photonic device applications.

Hyperbolic metasurfaces have attracted much interest due to novel optical properties including self-focusing, diffraction-less propagation, and negative refraction. However, conventional hyperbolic metasurfaces employing transverse-magnetic-like (TM-like) guided modes operate limited to short wavelengths. Here, we propose a broadband hyperbolic metasurface utilizing the transverse-electric-like (TE-like) guided modes of silver nanowires. The symmetric TE-like mode of the nanowire metasurface supports strong near-field coupling through the metallic element for hyperbolicity from visible to near-infrared wavelengths. Using numerical simulations, we examine the modal and dispersion properties depending on the wavelength and geometry. Particularly, negative refraction at the interface between a hyperbolic metasurface and the normal-dispersion planar waveguide is also demonstrated.