Experimental determination of the dispersion relation of light in metamaterials by white-light interferometry

We present a method to experimentally measure the complex reflection and transmission coefficients of optical waves at metamaterials under normal incidence. This allows us to determine their pertinent dispersion relation without resorting to numerical simulations. For this purpose we employ a spectrometer and a white light interferometer for amplitude and phase measurements, respectively. To demonstrate the reliability of the method, it is applied to two referential metamaterial geometries, namely, the fishnet and the double-element structure. Involved aspects of the phase measurements as well as the accuracy of the method are discussed. (C) 2010 Optical Society of America