Fabrication and Unique Optical Properties of Two-Dimensional Silver Nanorod Arrays with Nanometer Gaps on a Silicon Substrate from a Self-Assembled Template of Diblock Copolymer.

A periodic array of nanoholes was fabricated via the self-assembly of a polystyrene(PS)-b-poly(methyl methacrylate) (PMMA) block copolymer (BCP) on a silicon substrate and selective etching of the PMMA moieties. Silver nanorods (AgNRs) were then selectively deposited in the nanoholes by a galvanic displacement reaction where the pattern was hexagonally aligned according to the template. The diameter of AgNRs was controlled by changing the immersion time.

Sensitivity to refractive index of high-aspect-ratio nanofins with optical vortex.

An easy and large-scale fabrication technique of metal fins was used to produce periodic Au fin arrays that realized light confinement in the near-infrared region. Light confinement was revealed by vortex patterns in the optical power flow of an array of high-aspect-ratio fins (height of 1000 nm for a width of 50 nm). The light confinement resulted in sharp dips in the reflectance spectrum of the high-aspect-ratio fin array.