title: Sensitivity to refractive index of high-aspect-ratio nanofins with optical vortex.
abstract: 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. The wavelengths of the reflectance dips were found to shift toward higher values when the refractive index of the surrounding medium was increased. Experimental and simulated dip shift values were in good agreement with a demonstrated sensitivity of 580 nm per refractive index unit.
authors.affiliation: School of Engineering, The University of Tokyo, 7-3-1 Hongo, Tokyo 113-8656, Japan.
authors.forename: Etsuo
authors.initials: E
authors.lastname: Maeda
authors.forename: Yaerim
authors.initials: Y
authors.lastname: Lee
authors.forename: Youjiro
authors.initials: Y
authors.lastname: Kobayashi
authors.forename: Akiko
authors.initials: A
authors.lastname: Taino
authors.forename: Mari
authors.initials: M
authors.lastname: Koizumi
authors.forename: Shigenori
authors.initials: S
authors.lastname: Fujikawa
authors.forename: Jean-Jacques
authors.initials: JJ
authors.lastname: Delaunay