Almost 40 years ago Russian scientist Victor Veselago had an idea for a material that could turn the world of optics on its head. It could make light waves appear to flow backward and behave in many other counterintuitive ways. A totally new kind of lens made of the material would have almost magical attributes that would let it outperform any previously known. The catch: the material had to have a negative index of refraction ("refraction" describes how much a wave will change direction as it enters or leaves the material). All known materials had a positive value. After years of searching, Veselago failed to find anything having the electromagnetic properties he sought, and his conjecture faded into obscurity.
A startling advance recently resurrected Veselago's notion. In most materials, the electromagnetic properties arise directly from the characteristics of constituent atoms and molecules. Because these constituents have a limited range of characteristics, the millions of materials that we know of display only a limited palette of electromagnetic properties. But in the mid-1990s one of us (Pendry), in collaboration with scientists at Marconi Materials Technology in England, realized that a "material" does not have to be a slab of one substance. Rather it could gain its electromagnetic properties from tiny structures, which collectively create effects that are otherwise impossible.
This article was originally published with the title The Quest for the Superlens.