Berlin 2005 – scientific programme

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AKB: Biologische Physik

AKB 100: Poster Session I

AKB 100.68: Poster

Saturday, March 5, 2005, 16:45–18:45, Poster TU D

High resolution CARS microscopy with chirped excitation — •Ondrej Burkacky and Andreas Zumbusch — Department Chemie, LMU München, Butenandtstraße 11, 81377 München

Coherent anti-Stokes Raman scattering (CARS) microscopy puts us in a position to obtain molecular information at high spatial resolution without the use of labels. Both chemical composition and structural features are visualized by their vibrational spectra.

For efficient signal generation in the nonlinear processes involved, ultrashort laser pulses with high peak intensities are needed. However, the corresponding broad bandwidths limit the spectral resolution achieved. Therefore we introduced the method of chirping the pulses in a well-controlled manner. This leads to a narrower instantaneous bandwidth of the chirped pulses and consequently to a higher spectral resolution. In addition, the narrow spectral region probed can be shifted within the range of the much broader laser bandwidth of the ultrashort laser pulses by simply varying the temporal delay between the two pulses. We demonstrate how this approach can be used to obtain spectral and spatial high resolution images with large contrast in a variety of specimens.

Th. Hellerer, A.M.K. Enejder, A. Zumbusch, Appl. Phys. Lett. 85 (2004) 25