Non-linear vibrational microscopy
Date | Do, 19.05.2011 | |
Time | 10.15 | |
Speaker | Prof. Dr. Andreas Zumbusch, Department Chemie, Universität Konstanz, 78457 Konstanz | |
Location | Universität Bern, Institut für Angewandte Physik, Gebäude exakte Wissenschaften, Hörsaal B116, Sidlerstrasse 5, 3012 Bern | |
Program | During the last decade, ultrasensitive microscopy has become one of the most important tools in biophysics. Most prominent among the various techniques is confocal fluorescence microscopy. It is a very widespread technique with which sensitivities down to the single molecule detection limit can be achieved. In applications of fluorescence microscopy, however, one faces two problems: i) In most cases, the samples need to be labeled with a fluorophore which can be difficult and can change the properties of the sample. ii) All fluorophores are prone to photobleaching which severely limits the maximum achievable observation times. In order to solve these problems, recent years have seen the development of a broad variety of different techniques, which generate contrast without the need of external staining. In this talk, Coherent Anti-Stokes Raman Scattering (CARS) microscopy providing chemically selective imaging will be presented 1. CARS microscopy is a non-linear optical technique in which two laser frequencies are used to excite the sample simultaneously. If the frequencies are chosen such that their difference coincides with a vibrational transition of the sample, a strong signal which is higher in energy than the excitation beams is generated. Apart from its biological applications, CARS microscopy has recently attracted a lot of attention as an application field for modern approaches of ultrafast spectroscopy 2,3. As an outlook, I will discuss ways to detect time resolved vibrational spectra of single molecules. 1 M. Müller, A. Zumbusch "Coherent Anti-Stokes Raman Scattering (CARS) microscopy" ChemPhysChem, 8 (2007) 2156- 2169 2 G. Krauss, T. Hanke, A. Sell, D. Träutlein, A. Leitenstorfer. R. Selm. M. Winterhalder, A. Zumbusch "A compact coherent anti-Stokes Raman scattering microscope based on a picosecond two-color Er:fiber laser system", Opt. Lett., 34 (2009) 2847-2849 3 R. Selm, M. Winterhalder, A. Zumbusch, G. Krauß, T. Hanke, A. Sell, A. Leitenstorfer” Ultrabroadband background-free Coherent anti-Stokes Raman Scattering microscopy based on a compact Er:fiber laser system”, Opt. Lett., 35 (2010) 3282- 3284 4 M. Winterhalder, A. Zumbusch, M. Lippitz, M. Orrit, "Towards Far-Field Vibrational Spectroscopy of Single Molecules at Room Temperature" J. Phys. Chem. B, in press |
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Link | www.iap.unibe.ch |