Nonlocal electrodynamics of homogenized metal-dielectric photonic crystals

The nonlocal effective permittivity tensor for photonic crystals (PCs), having dielectric and metallic inclusions in the unit cell, is calculated and analyzed within the homogenization theory based on the Fourier formalism and the form-factor division approach. A method allowing us to extract the effective bianisotropic metamaterial parameters (permeability and chirality) from the wave vector dependence of the nonlocal effective dielectric response is proposed. Both the original nonlocal dielectric response parameters and the new bianisotropic metamaterial ones reproduce the photonic band structure of the artificial crystal far beyond the long wavelength limit and for a wide class of metal-dielectric structures. To calculate the optical spectra (reflection and transmission) of finite-size PC, the nonlocal homogenization approach is extended with the method of expansion into photonic bulk-modes (Bloch waves). The application of the developed theory is illustrated with well-known forms of metallic inclusions (slabs, thin wires, split-ring resonators) and experimentally confirmed with novel designs based on metallic crosses.