The quest for the superlens.

This article explores the development of a superlens that would allow imaging of details finer than the wavelength of light used. Materials made out of carefully fashioned microscopic structures can have electromagnetic properties including a negative index of refraction, which means they refract light in a totally new way. A slab of negative-index material could act as a superlens, able to outperform today's lenses, which have a positive index. Such a superlens could create images that include detail finer than that allowed by the diffraction limit, which constrains the performance of all positive-index optical elements. Although most experiments with metamaterials are performed with microwaves, they might use shorter infrared and optical wavelengths in the future.