In all known naturally occurring materials, the real part of the index of refraction is positive. However, as shown in reference , this is not a fundamental restriction. It is possible to create negative refraction with left-handed materials – materials whose electrical permittivity and magnetic permeability are simultaneously negative in certain frequency bands. Recently, several artificially structured left-handed meta-materials have been introduced (reference ) and analytical analysis has shown surprising results (references [1,3]). The properties of these new materials are of some considerable interest.
RSoft's FullWAVE, based on the FDTD technique for solving Maxwell's equations, is a very suitable tool for modeling negative index metamaterials: the requirement that ε and μ be simultaneously negative implies a frequency-dependent dispersion model for both properties, which FullWAVE can include with ease. This application note utilizes FullWAVE to investigate the transmission characteristics of a finite Gaussian beam incident through a material with negative refractive index: we present two negative index examples, a negative prism and a negative lens, both with ε = μ = -1. In addition to this application note, please refer to "Tutorial #12 – Negative Refractive Index" in the FullWAVE manual for further details about simulating negative-index metamaterials in FullWAVE.