Anisotropic medium with parabolic dispersion

A layered metamaterial which is predicted by the effective medium theory to be an anisotropic medium with partial zero permittivities is analyzed carefully. It is shown that such a material has a dispersion relation in parabolic form, which is quite different from the known ones. This material may be viewed as a homogeneous medium but is spatially dispersive strongly. The structured medium may support either forward wave or backward wave, depending on the magnitude of the wave vector. Moreover, it is demonstrated that this medium with parabolic dispersion is especially suitable for the transmission of Gaussian beam with subwavelength width. (c) 2008 American Institute of Physics.