Berlin 2015 – scientific programme

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BP: Fachverband Biologische Physik

BP 1: Imaging

BP 1.10: Talk

Monday, March 16, 2015, 12:15–12:30, H 1028

Three-dimensional orientation imaging of single fluorescent emitter transition dipoles — •Narain Karedla, Anna Chizhik, Ingo Gregor, Alexey Chizhik, and Jörg Enderlein — 3. Physikalisches Institut, Georg-August-Universität Göttingen

Fluorescent molecules behave as electric dipole emitters with fixed but typically distinct excitation and emission dipole orientations. In the vicinity of dielectric or conducting surfaces, the emission properties of a dye molecule such as the emission rate (Purcell effect) and angular distribution of radiation are dramatically changed. Utilizing these effects, we develop a first-ever method, by combining radially-polarized laser scanning together with imaging on a defocused EMCCD camera in a way that provides excitation and emission patterns of each individual dye molecule, which gives us the three-dimensional orientations of both the excitation and emission dipole. Furthermore, using the orientation information of the emission dipole with respect to the interface, we localize single emitters axially from the interface with nanometer accuracy, a technique which we term as single-molecule metal-induced energy transfer (smMIET). This method is ideal for investigating the dimensionality and orientations of the TDMs of quantum dots, which are substantially modified in the vicinity of metal nanostructures.