P. Vodo, P. V. Parimi, W. T. Lu and S. Sridhar
Applied Physics Letters, V.86, P.201108 (2005)
We demonstrate focusing of a plane microwave by a planoconcave lens fabricated from a photonic crystal having a negative refractive index and left-handed electromagnetic properties. An inverse experiment, in which a plane wave is produced from a source placed at the focal point of the lens, is also reported. A frequency-dependent negative refractive index, n(ω) < 0 is obtained for the lens from the experimental data which match well with that determined from band structure calculations.