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Q: Fachverband Quantenoptik und Photonik

Q 21: Poster I

Q 21.77: Poster

Dienstag, 9. März 2010, 16:00–19:00, Lichthof

Ultra-sensitive fluorescence spectroscopy of isolated surface-adsorbed molecules using an optical nanofiber — •Ariane Stiebeiner, David Papencordt, Nils Konken, Ruth Garcia-Fernandez, and Arno Rauschenbeutel — QUANTUM, Institut für Physik, Johannes Gutenberg-Universität Mainz, 55099 Mainz

The strong radial confinement and the pronounced evanescent field of the guided light in optical nanofibers allow the controlled interaction with particles which are deposited near or on the fiber surface. Using the guided mode of the nanofiber waist of a tapered optical fiber for excitation and fluorescence collection, we present spectroscopic measurements on surface-adsorbed organic dye molecules. In order to efficiently couple light into and out of the nanofiber over a broad spectral range, we have optimized the taper geometry based on numerical simulations and experimental studies. As a result, surface coverages as small as 0.1 % of a compact monolayer still give rise to fluorescence spectra with a good signal to noise ratio. The effect of self-absorption in our system can be quantitatively modelled and is negligible for low surface coverages. We are currently setting up a cryogenic apparatus for low temperature measurements. The new setup, together with the high sensitivity of our method, should allow us to perform nanofiber-based spectroscopy on the single molecule level.

We gratefully acknowledge financial support by the EC (STREP "CHIMONO"), the ESF (EURYI), and the Volkswagen Foundation (Lichtenberg Professorship).