title: The controlled fabrication and geometry tunable optics of gold nanotube arrays.
abstract: Arrays of vertically aligned gold nanotubes are fabricated over several square centimetres which display a geometry tunable plasmonic extinction peak at visible wavelengths and at normal incidence. The fabrication method gives control over nanotube dimensions with inner core diameters of 15-30 nm, wall thicknesses of 5-15 nm and nanotube lengths of up to 300 nm. It is possible to tune the position of the extinction peak through the wavelength range 600-900 nm by varying the inner core diameter and wall thickness. The experimental data are in agreement with numerical modelling of the optical properties which further reveal highly localized and enhanced electric fields around the nanotubes. The tunable nature of the optical response exhibited by such structures could be important for various label-free sensing applications based on both refractive index sensing and surface-enhanced Raman scattering.
authors.affiliation: Centre for Nanostructured Media, IRCEP, The Queen's University of Belfast, Belfast BT7 1NN, UK. amurphy22@qub.ac.uk
authors.forename: Antony
authors.initials: A
authors.lastname: Murphy
authors.forename: John
authors.initials: J
authors.lastname: McPhillips
authors.forename: William
authors.initials: W
authors.lastname: Hendren
authors.forename: Christina
authors.initials: C
authors.lastname: McClatchey
authors.forename: Ron
authors.initials: R
authors.lastname: Atkinson
authors.forename: Gregory
authors.initials: G
authors.lastname: Wurtz
authors.forename: Anatoly V
authors.initials: AV
authors.lastname: Zayats
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Pollard