Near-field imaging of a square-lattice metallic photonic-crystal slab at the second band

Imaging properties of a two-dimensional photonic crystal slab lens areinvestigated through the finite-difference time-domain method. In thispaper, we consider the photonic crystal slab consisting of a square latticeof square metallic rods immersed in a dielectric background. Through theanalysis of the equifrequency-surface contours and the field patterns of apoint source placed in the vicinity of the photonic crystal slab, we findthat a good-quality image can form at the frequencies in the secondTM-polarized photonic band. Comparing the images formed at differentfrequencies, we can clearly see that an excellent-quality image is formed bythe mechanisms of simultaneous action of the self-collimation effect and thenegative-refraction effect.