title: Plasmonic coupling and long-range transfer of an excitation along a DNA nanowire.
abstract: We demonstrate an excitation transfer along a fluorescently labeled dsDNA nanowire over a length of several micrometers. Launching of the excitation is done by exciting a localized surface plasmon mode of a 40 nm silver nanoparticle by 800 nm femtosecond laser pulses via two-photon absorption. The plasmonic mode is subsequently coupled or transformed to excitation in the nanowire in contact with the particle and propagated along it, inducing bleaching of the dyes on its way. In situ as well as ex situ fluorescence microscopy is utilized to observe the phenomenon. In addition, transfer of the excitation along the nanowire to another nanoparticle over a separation of 5.7 μm was clearly observed. The nature of the excitation coupling and transfer could not be fully resolved here, but injection of an electron into the DNA from the excited nanoparticle and subsequent coupled transfer of charge (Dexter) and delocalized exciton (Frenkel) is the most probable mechanism. However, a direct plasmonic or optical coupling and energy transfer along the nanowire cannot be totally ruled out either. By further studies the observed phenomenon could be utilized in novel molecular systems, providing a long-needed communication method between molecular devices.
authors.affiliation: Institute of Photonic Technology, Albert-Einstein-Strasse 9, Jena 07745, Germany.
authors.forename: J Jussi
authors.initials: JJ
authors.lastname: Toppari
authors.forename: Janina
authors.initials: J
authors.lastname: Wirth
authors.forename: Frank
authors.initials: F
authors.lastname: Garwe
authors.forename: Ondrej
authors.initials: O
authors.lastname: Stranik
authors.forename: Andrea
authors.initials: A
authors.lastname: Csaki
authors.forename: Joachim
authors.initials: J
authors.lastname: Bergmann
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Paa
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Fritzsche
mesh_terms: D004247:DNA / Q000737:chemistry*; D005456:Fluorescent Dyes / Q000737:chemistry; D053768:Metal Nanoparticles / Q000737:chemistry; D053770:Nanowires / Q000737:chemistry*; D055585:Physical Phenomena; D012834:Silver / Q000737:chemistry
chemical_list: D005456:Fluorescent Dyes; D012834:Silver; D004247:DNA