Controlled-reflectance surfaces with film-coupled colloidal nanoantennas

摘要: Efficient and tunable absorption is essential for a variety of applications, such as designing controlled-emissivity surfaces thermophotovoltaic devices, tailoring an infrared spectrum controlled thermal dissipation producing detector elements imaging. Metamaterials based on metallic are particularly efficient absorbing media, because both the electrical magnetic properties metamaterial can be tuned by structured design. So far, absorbers in or visible range have been fabricated using lithographically patterned structures, making them inherently difficult to produce over large areas hence reducing their applicability. Here we demonstrate simple method create absorber randomly adsorbing chemically synthesized silver nanocubes onto nanoscale-thick polymer spacer layer gold film, no effort control spatial arrangement cubes film. We show that film-coupled provide reflectance tailored varying geometry (the size and/or thickness spacer). Each nanocube optical analogue grounded patch antenna, with nearly identical local field structure modified plasmonic response metal's dielectric function, anomalously efficiency partly attributed interferometric effect. The absorptivity surface this method, at scales out reach lithographic approaches (such electron-beam lithography) otherwise required manipulate matter nanoscale.