title: Tuning localized transverse surface plasmon resonance in electricity-selected single-wall carbon nanotubes by electrochemical doping.
abstract: Localized surface-plasmon resonance affects the optical absorption and scattering of nanosized materials. The intensities and peak energies of the surface plasmons strongly depend on the carrier density; thus, the optical absorption peaks originating from the surface-plasmon resonance can be manipulated by the density of injected carriers. In single-wall carbon nanotubes (SWCNTs), the correct identification of surface-plasmon resonance modes is of great interest due to their emerging plasmonic and optoelectronic applications. Here, we demonstrate that high-carrier injection by electric double layers can induce a transverse surface-plasmon peak in aggregated, electricity-selected SWCNTs. In contrast to the well-discussed surface-plasmon resonance mode, whose polarization is parallel to the axis and whose resonance frequency is located in the THz region, our identified mode, which was normal to the axis, was located in the near-infrared range. In addition, our mode's peak position and intensities were tunable by carrier injections, indicating a route to control plasmonic optical processes by electric double-layer carrier injections using ionic liquid.
authors.affiliation: Department of Physics, Tokyo Metropolitan University, Tokyo 192-0397, Japan.
authors.forename: Toru
authors.initials: T
authors.lastname: Igarashi
authors.affiliation: Department of Physics, Tokyo Metropolitan University, Tokyo 192-0397, Japan.
authors.forename: Hideki
authors.initials: H
authors.lastname: Kawai
authors.affiliation: Department of Physics, Tokyo Metropolitan University, Tokyo 192-0397, Japan.
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Yanagi
authors.affiliation: Nanosystem Research Institute (NRI), National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba 305-8568, Japan.
authors.forename: Nguyen Thanh
authors.initials: NT
authors.lastname: Cuong
authors.affiliation: Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8571, Japan.
authors.forename: Susumu
authors.initials: S
authors.lastname: Okada
authors.affiliation: Faculty of Physics, University of Vienna, Vienna A-1090, Austria.
authors.forename: Thomas
authors.initials: T
authors.lastname: Pichler