Nonlinear metamaterials

Nature has provided us with a wide range of materials exhibiting various electromagnetic properties. However, theoretical speculations [1] have suggested that having materials with some particular unnatural characteristics would enable us to observe very unusual and potentially useful effects, including negative refraction for interface scattering, inverse light pressure, reverse Doppler and Vavilov-Cherenkov effects, etc. Recently, the way to artificially make materials with desired properties was suggested theoretically [2, 3] and such materials were prepared experimentally [4-6]. Composite materials were made of a mixture of electric and magnetic resonators, so that they can provide simultaneously negative dielectric and magnetic response. In particular, the simplest composite materials of this type are created by a mesh of metallic wires and split-ring resonators (SRRs), and their unique properties are associated with negative real parts of magnetic permeability and dielectric permittivity. Such composite materials are often referred to as left-handed materials (LHMs) or materials with negative refractive index. Further developments in the area of complex resonant metamaterials have shown their potential for creating of an electromagnetic cloak [7].