Focusing by the two-dimension photonic crystals

We investigate the square-lattice dielectric photonic crystals that have been used to demonstrate flat slab focusing experimentally by Parimi et al. Using the multiple scattering methods, we have demonstrated that the left-handed mode and the right-handed mode are excited simultaneously. After changing the radius of the alumina rods, the focusing properties of this photonic crystal slab are dominantly governed by the negative refraction effect because the left-handed mode is strongly enhanced while the right-handed mode is strongly suppressed.