Left-handed Band in an Electromagnetic Metamaterial Inducedby Sub-wavelength Multiple Scattering

Metamaterials often use a quasi-static approximation because their unit cells are deeply sub-wavelength. This study argues that even at that scale, multiple scattering between resonators can produce additional resonant behavior. The authors form pairs of resonators and show that this multiple scattering leads to a dipolar resonance. When several resonators are considered, the resulting response yields a negative index of refraction. They report experimental verification of negative refractive index in periodic metamaterials using two different approaches, and they further demonstrate a superlensing effect in both cases.