title: Quantitative and Direct Near-Field Analysis of Plasmonic-Induced Transparency and the Observation of a Plasmonic Breathing Mode.
abstract: We investigated experimentally and numerically in the optical near-field a plasmonic model system similar to a dolmen-type structure for phenomena such as plasmon-induced transparency. Through engineering of coupling strength, structure orientation, and incident angle and phase of the excitation source it was possible to control near-field excitation of the dark modes. We showed that quantitative analysis of near-field amplitude and excitation strength provided essential information that allowed identifying the interaction between the bright and the dark mode and how it causes the formation of plasmon-induced transparency features and a Fano resonance. In addition, we introduced a mechanism to excite field distributions in plasmonic structures that cannot be accessed directly using far-field illumination and demonstrated the excitation of a dark mode akin to a symmetry-forbidden plasmonic breathing mode using a linearly polarized far-field source.
authors.affiliation: Max-Planck-Institut für Festkörperforschung , Heisenbergstraße 1, 70569 Stuttgart, Germany.|The Blackett Laboratory, Department of Physics, Imperial College London , London SW7 2AZ, United Kingdom.
authors.forename: Worawut
authors.initials: W
authors.lastname: Khunsin
authors.affiliation: Max-Planck-Institut für Festkörperforschung , Heisenbergstraße 1, 70569 Stuttgart, Germany.|4. Physikalisches Institut und Research Center SCoPE, Universität Stuttgart , Pfaffenwaldring 57, 70569 Stuttgart, Germany.
authors.forename: Jens
authors.initials: J
authors.lastname: Dorfmüller
authors.affiliation: Max-Planck-Institut für Festkörperforschung , Heisenbergstraße 1, 70569 Stuttgart, Germany.
authors.forename: Moritz
authors.initials: M
authors.lastname: Esslinger
authors.affiliation: Max-Planck-Institut für Festkörperforschung , Heisenbergstraße 1, 70569 Stuttgart, Germany.|Carl von Ossietzky Universität Oldenburg , 26129 Oldenburg, Germany.
authors.forename: Ralf
authors.initials: R
authors.lastname: Vogelgesang
authors.affiliation: Institute of Theoretical Solid State Physics, Karlsruhe Institute of Technology , Wolfgang-Gaede-Straße 1, 76131 Karlsruhe, Germany.|Institute of Nanotechnology, Karlsruhe Institute of Technology , P.O. Box 3640, 76021 Karlsruhe, Germany.
authors.forename: Carsten
authors.initials: C
authors.lastname: Rockstuhl
authors.affiliation: Institut für Festkörpertheorie und -optik, Abbe Center of Photonics, Friedrich-Schiller-Universität Jena , Max-Wien-Platz 1, 07743 Jena, Germany.
authors.forename: Christoph
authors.initials: C
authors.lastname: Etrich
authors.affiliation: Max-Planck-Institut für Festkörperforschung , Heisenbergstraße 1, 70569 Stuttgart, Germany.|Institut de Physique de la Matière Condensée, École Polytechnique Fédérale de Lausanne , 1015 Lausanne, Switzerland.
authors.forename: Klaus
authors.initials: K
authors.lastname: Kern
keywords: EIT; Fano resonance; PIT; breathing mode; dark modes; plasmonics; scanning near-field optical microscopy