title: Double-layered nanoparticle stacks for surface enhanced infrared absorption spectroscopy.
abstract: We demonstrate that double-layered stacks of gold and insulator nanoparticles arranged on a flat gold surface dramatically enhance the sensitivity in absorption infrared microscopy. Through morphological variations of the nanoparticles, the frequency of the plasmon resonances can be tuned to match the frequency of the molecular vibration in the mid-infrared region. The results show that the nanostructures enhance the absorption signal of the molecules by a factor of up to ~2.2 × 10(6), while preserving their characteristic line-shape remarkably well.
authors.affiliation: Austrian Institute of Technology GmbH, AIT, Donau-City Str. 1, 1220 Vienna, Austria. C.Nowak@ait.ac.at.
authors.forename: Johannes
authors.initials: J
authors.lastname: Srajer
authors.forename: Andreas
authors.initials: A
authors.lastname: Schwaighofer
authors.forename: Georg
authors.initials: G
authors.lastname: Ramer
authors.forename: Stefan
authors.initials: S
authors.lastname: Rotter
authors.forename: Bilal
authors.initials: B
authors.lastname: Guenay
authors.forename: Albert
authors.initials: A
authors.lastname: Kriegner
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Knoll
authors.forename: Bernhard
authors.initials: B
authors.lastname: Lendl
authors.forename: Christoph
authors.initials: C
authors.lastname: Nowak