Probing guided modes in a monolayer colloidal crystal on a flat metal film

Two-dimensional slab hybrid metal-dielectric photonic crystals, which are prepared by assembling polymer colloidal spheres into closely packed monolayers of hexagonal symmetry on a gold-coated glass substrate, show an improved confinement of light compared with a colloidal monolayer on a glass substrate. We demonstrated that the optical response of such hybrid crystals consists of diffractively coupled waveguiding modes, Fabry-Perot resonances, and Mie resonances. Correspondingly, two major mechanisms, namely, band transport and hopping of localized excitations, participate in the in-plane light transport in such hybrid crystals.