Near-field, broadband optical spectroscopy of metamaterials

Near-field, broadband optical spectroscopy of metamaterials is reported. A compact, easy to assemble supercontinuum light source, coupled with a near-field scanning optical microscope and spectrometer provide the means to locally probe the spectral response of a nanorod metamaterial sample. Spectral maps of near-field transmittance are obtained for the spectral range from 500 to 950 nm. In comparison to far-field measurement, the average of the near-field mappings shows a significant increase in transmittance. The uniqueness of the spectral maps and the increased transmittance indicates a strong nanoantenna effect between the sample and the plasmonic near-field aperture.