title: One-dimensional surface phonon polaritons in boron nitride nanotubes.
abstract: Surface polaritons, which are electromagnetic waves coupled to material charge oscillations, have enabled applications in concentrating, guiding and harvesting optical energy below the diffraction limit. Surface plasmon polaritons involve oscillations of electrons and are accessible in noble metals at visible and near-infrared wavelengths, whereas surface phonon polaritons (SPhPs) rely on phonon resonances in polar materials, and are active in the mid-infrared. Noble metal surface plasmon polaritons have limited applications in the mid-infrared. SPhPs at flat interfaces normally possess long polariton wavelengths and provide modest field confinement/enhancement. Here we demonstrate propagating SPhPs in a one-dimensional material consisting of a boron nitride nanotube at mid-infrared wavelengths. The observed SPhP exhibits high field confinement and enhancement, and a very high effective index (neff~70). We show that the modal and propagation length characteristics of the SPhPs may be controlled through the nanotube size and the supporting substrates, enabling mid-infrared applications.
authors.affiliation: Department of Chemistry, University of Toronto, Toronto, Ontario, Canada M5S 3H6.
authors.forename: Xiaoji G
authors.initials: XG
authors.lastname: Xu
authors.affiliation: School of Electrical Engineering and Computer Science, University of Ottawa, Ottawa, Ontario, Canada K1N 6N5.
authors.forename: Behnood G
authors.initials: BG
authors.lastname: Ghamsari
authors.affiliation: Department of Physics, University of Toronto, Toronto, Ontario, Canada M5S 1A7.
authors.forename: Jian-Hua
authors.initials: JH
authors.lastname: Jiang
authors.affiliation: Department of Chemistry, University of Toronto, Toronto, Ontario, Canada M5S 3H6.
authors.forename: Leonid
authors.initials: L
authors.lastname: Gilburd
authors.affiliation: Bruker Nano Surfaces Division, 112 Robin Hill Road, Santa Barbara, California 93117, USA.
authors.forename: Gregory O
authors.initials: GO
authors.lastname: Andreev
authors.affiliation: Department of Physics and Material Science, City University of Hong Kong, Hong Kong, China.
authors.forename: Chunyi
authors.initials: C
authors.lastname: Zhi
authors.affiliation: World Premier International (WPI) Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), Tsukuba, Ibaraki 305-0044, Japan.
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Bando
authors.affiliation: World Premier International (WPI) Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), Tsukuba, Ibaraki 305-0044, Japan.
authors.forename: Dmitri
authors.initials: D
authors.lastname: Golberg
authors.affiliation: 1] School of Electrical Engineering and Computer Science, University of Ottawa, Ottawa, Ontario, Canada K1N 6N5 [2] Department of Physics, University of Ottawa, Ottawa, Ontario, Canada K1N 6N5.
authors.forename: Pierre
authors.initials: P
authors.lastname: Berini
authors.affiliation: Department of Chemistry, University of Toronto, Toronto, Ontario, Canada M5S 3H6.
authors.forename: Gilbert C
authors.initials: GC
authors.lastname: Walker