Metal-polymer nanocomposite films with ordered vertically-aligned metal cylinders for optical application

Ordered nanostructures of conventional plasmonic metals (Ag, Au etc.) in a dielectric matrix are candidate materials for fabrication of metamaterials. Control over the dimensions of these building blocks offers tunability in the metamaterial design. To that effect we demonstrated the large area fabrication of poly(styrene-b-4-vinyl pyridine) (PS-b-P4VP) diblock copolymer films wherein the self assembly of the PS and P4VP phases creates monodisperse hexagonal cylindrical nanotemplates whose structure can be controlled by varying the molecular weights, layer thicknesses and layer stacking. Silver and gold precursors were infused into the P4VP micro domains and chemically reduced within. We investigated the PS-b-P4VP template film synthesis and successfully obtained micro domain sizes from 30nm to 100nm and template thicknesses up to 700 nm (5 layers) was achieved. The P4VP micro domains were selectively removed by acetic acid etching which was further confirmed by Atomic Force Microscopy (AFM) using the high aspect ratio tips. Using oxygen plasma etching we have shown the effective loading of gold and silver into the P4VP micro domains. Finite Difference Time Domain (FDTD) simulation of a proposed meta-lens with typical material dimensions demonstrates negative refraction and super-resolution imaging.