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Effective electromagnetic parameters of two-dimensional dielectric photonic crystal within band gap

We have investigated the effective electromagnetic parameters of a two-dimensional photonic crystal even though the wavelength is on the order of its lattice constant. For the photonic crystal within the first band gap, negative effective permittivity or negative effective permeability has been found. Utilizing the Finite-difference time-domain method, a flat slab imaging for TE waves in the near field has been demonstrated for the photonic crystal with effective negative permittivity which is similar to silver superlens for TM waves. Based on these results, we can conclude that photonic crystals in a certain frequency region can indeed mimic not only double-negative but also single-negative metamaterials.