The concept of a refractive index is familiar to every physicist: wine glasses sparkle, deep pools appear shallow and camera lenses focus sharp images. As every physics student knows, Snell's law relates the angles of incidence and refraction in materials with different refractive indices. However, physicists at the University of California at San Diego have now made a material with a negative refractive index.
In the June issue of Physics World magazine, John Pendry from Imperial College in London, explains how they made this unusual material and describes its various properties.