Berlin 2001 – wissenschaftliches Programm

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CPP: Chemische Physik und Polymerphysik

CPP 2: Single Molecule Spectroscopy

CPP 2.5: Vortrag

Dienstag, 3. April 2001, 17:05–17:25, 110

Imaging of the Interaction Potential of a single Molecule with a surface — •Christian Hettich, Carmen Schmitt, Jan Zitzmann, Sergei Kühn, and Vahid Sandoghdar — Universität Konstanz, Fachbereich Physik, Fach M696, D-78457 Konstanz, Germany, http://www.uni-konstanz.de/quantum-optics/nano-optics

Recently we have shown that a molecule inside a micro-crystal can be used as a point-like light source in microscopy[1]: By measuring the intesity of the fluorescence the local transmission through a sample can be imaged. Due to the small linewidth of terrylen in para-terphenyl at low temperatures a single terrylene molecule can be used as a sensitive local probe. In the latest experiments we use our low-temperature SNOM setup to position a silver-coated sphere of 6µm diameter in front of a nano-crystal. While approaching the sphere towards the molecule down to sub-micrometer distances, we observe a shift of the zero phonon line of the molecule of up to 6GHz which we account to the Stark effect. By moving the crystal in the lateral direction while measuring the line shift, we can determine the position of the molecule with unprecedented precision. This can be exploited in a novel method of high resolution optical microscopy [2].

[1] J. Michaelis, C. Hettich, J. Mlynek and V. Sandoghdar, Nature 405, 325 (2000).

[2] C. Henkel and V. Sandoghdar, Opt. Comm. 158, 250 (1998).