Dresden 2014 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 46: Plasmonics and Nanooptics I
O 46.6: Vortrag
Mittwoch, 2. April 2014, 11:45–12:00, TRE Phy
Third harmonic spectroscopy of single Au- nanoantennas fabricated by helium ion beam milling — •Heiko Kollmann1, Martin Esmann1, Simon F. Becker1, Xianji Piao2, Chuong Huynh3, Lars-Oliver Kautschor3, Guido Bösker3, Henning Vieker4, Armin Gölzhäuser4, Namkyoo Park2, Martin Silies1, and Christoph Lienau1 — 1University of Oldenburg, Germany — 2Seoul National University, Korea — 3Carl Zeiss Microscopy GmbH, Jena, Germany — 4University of Bielefeld, Germany
Metallic nanoantennas are able to localize far-field electromagnetic waves in volumes of a fraction of their wavelength. Standard tools for fabricating these structures with sub-20-nm feature sizes are Electron Beam Lithography or Ga-based Focused Ion Beam (FIB) milling. Here, we combine Ga- and He-ion based milling (HIM) for the fabrication of gold bow-tie antennas with few-nanometer gap sizes. Using polarization-sensitive Third-Harmonic (TH) spectroscopy, we compare the nonlinear optical properties of single HIM-antennas with sub-6-nm gaps with those produced by Gallium-based FIB. We find a pronounced enhancement of the intensity and a greatly improved polarization contrast of the TH for He-ion produced antennas in comparison with state-of-the-art Ga-FIB antennas. Our experimental findings are strongly supported by FEM calculations and demonstrate electric field localization in the few-nanometer gap of the bow-tie antenna. This makes He-ion beam milling a highly attractive and promising new tool for the fabrication of plasmonic nanoantennas with few-nanometer feature sizes.