Fig. 1

Schematic of metamaterials composed of Ag nanodisks and a SiO₂ spacer on Ag substrate. Geometrical parameters: p _x and p _y are the array periods along the x and y directions, respectively; t is the thickness of the SiO₂ spacer; d and h are the diameter and the height of the Ag nanodisks. E _in, H _in, and K _in are the electric field, magnetic field, and wave vector of the incident light, which are along the x, y, and z axes, respectively