Focusing of electromagnetic waves by periodic arrays of dielectric cylinders

By numerical simulations, we show that properly arranged two dimensional periodic arrays, formed by dielectric cylinders embedded in parallel in a uniform medium, can indeed act as an optical lens to focus electromagnetic waves, in accordance with the recent conjecture in the literature. The numerical simulations are based on an exact multiple scattering technique. The results suggest that the E-polarized waves are easier to be focused than the H-polarized waves. The robustness of the focusing against disorders is also studied. Comparison with the corresponding cases for acoustic waves is also discussed.