Nano Lett. (2008) 8, 3155-3159.
Link to paper

Direct Near-Field Optical Imaging of Higher Order Plasmonic Resonances

R. Esteban,*† R. Vogelgesang,*† J. Dorfmüller,† A. Dmitriev,‡ C. Rockstuhl,§ C. Etrich,∥ and K. Kern†⊥

Max Planck Institut für Festkörperforschung, 70569 Stuttgart, Germany, Bionanophotonics at Applied Physics, Chalmers University of Technology, 41296 Göteborg, Sweden, Institut für Festkörpertheorie and -optik and Institut für angewandte Physik, Friedrich-Schiller-Universität, 07743 Jena, Germany, and Institut de Physique des Nanostructures, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland

Received May 15, 2008

Revised July 17, 2008

Abstract:

We map in real space and by purely optical means near-field optical information of localized surface plasmon polariton (LSPP) resonances excited in nanoscopic particles. We demonstrate that careful polarization control enables apertureless scanning near-field optical microscopy (aSNOM) to image dipolar and quadrupolar LSPPs of the bare sample with high fidelity in both amplitude and phase. This establishes a routine method for in situ optical microscopy of plasmonic and other resonant structures under ambient conditions.