Metamaterials

"Metamaterials are artificial materials engineered to provide properties which may not be readily available in nature. These materials usually gain their properties from structure rather than composition, using the inclusion of small inhomogeneities to enact effective macroscopic behavior.

The primary area of research in metamaterials is investigation of materials with a negative refractive index, because after this was demonstrated, there has been an explosion of interest in the field. Negative refractive index materials appear to permit the creation of 'superlenses' which can have a spatial resolution below that of the wavelength, and a form of 'invisibility' has been demonstrated at least over a narrow wave band."

Such metamaterials are being studied in regards to such things as camouflage and a bunch of other interesting applications like remote aerospace applications. Further research is expected to extend use of metamaterials to bend the visible light spectrum. This would potentially make invisibility possible by bending light around the material.