Negative Index Materials: A New Frontier in Optics?

Almost thirty years after the initial theoretical study of hypothetical materials with negative effective index of refraction by Veselago, Pendry et al. designed an artificial structure, a split ring resonator (SRR), which would exhibit negative permeability. It took another two years for the first experimental demonstration of negative refraction in a composite structure consisting of SRRs and metallic wires by Shelby et al. During the last four years, this new and exciting field is growing fast. In this paper, some recent important results are presented and commented upon.