Negative refraction and rough surfaces: A new regime for lensing

The action of a rough, but differentiable, interface upon the passage of rays between air and a left-handed medium is considered. It is shown that negative refraction brings rays to a focus at distances closer to the boundary than can be attained by conventional refraction. This effect enables a new mechanism for reflection to occur, even in media that are impedance matched, caused principally by rays undergoing two interactions with the interface via paths that pass exclusively through air or the left-handed medium.