Negative Refraction and Imaging in a Triangular-Lattice Metallic Photonic-Crystal Slab

Imaging properties of a two-dimensional photonic crystal (PC) slab consisting of a triangular lattice of metallic cylinders immersed in a dielectric background are investigated by the finite-difference time-domain technique. With the calculated field patterns of a point source placed in the vicinity of the PC slab and the corresponding equifrequency-surface contours, we find that a high-quality image can form in the opposite side of the slab in the lowest TM-polarized photonic band, and this near-field image is formed mainly by the self-collimation effect.