Berlin 2015 – scientific programme

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O: Fachverband Oberflächenphysik

O 36: Plasmonics and Nanooptics

O 36.11: Poster

Tuesday, March 17, 2015, 18:15–21:00, Poster A

Imaging ring resonator plasmons using photoemission electron microscopy — •Deirdre Kilbane, Anna-Katharina Mahro, Pascal Melchior, Cristian González, Michael Hartelt, Philip Thielen, Markus Rollinger, Stefan Mathias, and Martin Aeschlimann — Physics Department and Research Centre OPTIMAS, University of Kaiserslautern, Germany

Understanding fundamental interactions of light and matter e.g. the dynamic response of a metal to incident light is essential for designing plasmonic devices such as biosensors. Ring resonators are ideal biosensors since the binding of a biomolecule alters the near-field response causing detectable changes in the resonance wavelength and intensity. Typically far-field optical detection techniques are used to determine the spectral properties of these nanoantennas. However the near field response is determined on a length scale that is intrinsically smaller than the optical diffraction limit. We therefore use electrons instead of photons for imaging the near-field distribution. We characterize arrays of ring resonators by combining photoemission electron microscopy (PEEM) with a tuneable excitation source, an optical parametric oscillator (OPO). These ultrahigh spatially and spectrally resolved measurements reveal resonance conditions for different ring radii and depths.