Silver high-aspect-ratio micro- and nanoimprinting for optical applications

Metal direct nanoimprinting is a fabrication technique based on plastic deformation of ductile metals such as silver and gold pressed into a structured rigid mold. While this process can be exploited to manufacture metallic micro- and nanoparts by removing the mold after processing, it can also be used as a metallization method for producing two-dimensional metallo-dielectric composites. Dense silver-pillar arrays with diameters down to 140 nm, aspect ratios up to 13, and excellent uniformity over large areas were fabricated. The sample quality was confirmed by near-infrared optical reflectances of Si-Ag photonic crystals, which showed strong collective surface plasmon-polariton resonances.