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DS: Fachverband Dünne Schichten

DS 28: [O] Plasmonics and Nanooptics IV (Joint Session DS/O/HL)

DS 28.1: Vortrag

Mittwoch, 24. März 2010, 15:00–15:15, H32

Raman and Luminescence Enhancement Produced in Gap-mode Near-field Optical Microscopy — •Dai Zhang, Marcus Sakrow, Kai Braun, and Alfred J. Meixner — Institute of Physical and Theoretical Chemistry, University Tübingen, Auf der Morgenstelle 8, Tübingen

Tip-enhanced near-field optical microscopy can produce spectroscopic images of molecular layers deposited on smooth Au-surfaces, of single molecules and of organic semi-conductor films with an optical resolution on the order of 10 nm. This is made possible by a sharp laser-illuminated Au-tip approaching as close as a few nanometers to the sample surface. The system behaves as an optical antenna for confining and enhancing the excitation field to a small sub-diffraction volume in the gap between the tip-apex and the surface and retrieving emitted or scattered photons to the far field for detection. In this way the signal emitted from the gap can be enhanced by several orders of magnitude with respect to the diffraction limited background signal by enhancing the excitation efficiency and the emission yield. In this contribution, a variety of enhancement mechanisms will be discussed.