Spatial dispersion and negative refraction of light
V.M. Agranovich a
Yu.N. Gartstein b
a Institute of Spectroscopy, Russian Academy of Sciences, ul. Fizicheskaya 5, Troitsk, Moscow, 108840, Russian Federation
b Department of Physics, The University of Texas at Dallas, Richardson, Texas, USA
Negative refraction at the interface between two media occurs as a natural consequence of wave group velocity being negative in one of the media. In this review the historical origins of this understanding are briefly described. A number of systems supporting normal electromagnetic waves (polaritons) with negative group velocity at optical frequencies are analyzed by including spatial dispersion and making use of the generalized dielectric tensor εij(ω, k), which determines the response of a medium to an electromagnetic wave of frequency ω and wave vector k. Negative group velocity polaritons occur when the
medium (whether a natural one or an artificial meta-material) has a sufficiently strong spatial dispersion. Examples of bulk waves
and surface waves are given both for chiral and nonchiral systems. The relationship between the εij(ω, k) approach and the more common but less comprehensive description using the dielectric permittivity ε(ω) and magnetic permeability μ(ω) is discussed.