Resonant photon transport through metal-insulator-metal multilayers consisting of Ag and SiO2

We have conducted experimental and numerical studies on resonant photon transport through Ag-SiO2-Ag multilayers with varying SiO2 gap-layer thickness due to its application toward the development of a metamaterial superlens. Photon-transport spectra that have been measured using a double-prism system with a p-polarized He-Ne laser show a resonant photon tunneling (RPT) peak in the total reflection region and an additional peak in the propagating region. Calculated dispersion curves and electric field profiles reveal that the RPT peak is brought about by antisymmetrically coupled surface-plasmon polaritons (SPPs), very similar to the long-range SPPs in a single-metal film. The additional peak, however, is caused by TM guided modes with symmetrically coupled SPPs. We demonstrate that the TM0 guided modes move continuously from the total reflecting region to the propagating region as the gap-layer thickness decreases. This will enable us to realize a device which converts evanescent waves into propagating waves of light, opening the possibility of an alternative type of hyperlens.