Negative refraction and focusing of electromagnetic waves by metallodielectric photonic crystals

In this work, we have experimentally and theoretically studied negative refraction of electromagnetic waves by a metallodielectric photonic crystal. We showed that by adding a periodic dielectric perturbation to the unit cell of a metallic photonic crystal, it is possible to increase the range of incidence angles at which the electromagnetic waves are negatively refracted. We obtained negative refraction for large incidence angles by the use of a metallodielectric photonic crystal. Furthermore, as an application of the negative refraction effect, we demonstrated the focusing of electromagnetic waves by the use of a metallodielectric photonic crystal. We obtained focusing of electromagnetic waves away from the surface of the photonic crystal. The observed focusing points are found to be larger than one wavelength away from the photonic crystal interface.