A visible metamaterial fabricated by self-assembly method

A visible negative-index metamaterial was fabricated by adopting a template-assisted and self-assembled electrochemical deposition method. Originating from the inherent characteristic of bottom-up fabrication, it has been demonstrated by the effective medium theory that the metamaterial resonance could realize a negative index at visible wavelengths if the degree of asymmetry is kept in a moderate range. This was experimentally substantiated by fabricating an asymmetric Ag–polyvinyl alcohol (PVA)–Ag multilayer nanostructure with two apertured silver films on the opposite sides of PVA film. The extraction of constitutive parameters shows negative index in the wavelength range from 535 to 565 nm, with a minimum value close to −0.5. Simultaneously, an optically active medium Rhodamine B was incorporated into the PVA layer, which readily changed the transmission peak through control experiments. Finally, the enhanced transmission was realized through a flat sample.