Toward superlensing with metal-dielectric composites and multilayers

We report on the fabrication of two types of adjustable, near-field superlens designs: metal–dielectric composites and metal–dielectric multilayer films. We fabricated a variety of films with different materials, thicknesses and compositions. These samples were characterized physically and optically to determine their film composition, quality, and optical responses. Our results on metal–dielectric composites indicate that although the real part of the effective permittivity generally follows effective medium theory predictions, the imaginary part does not and substantially higher losses are observed. Going forward, it appears that multilayer metal–dielectric designs are more suitable for sub-diffraction imaging applications because they could provide both tunability and low loss.