Hannover 2010 – wissenschaftliches Programm

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MO: Fachverband Molekülphysik

MO 24: Poster: Quantum Control

MO 24.4: Poster

Donnerstag, 11. März 2010, 16:00–18:30, Lichthof

Combining fs pulse tailoring and self-phase modulation for nonlinear microscopy — •Tillmann Kalas, Jens Köhler, Cristian Sarpe-Tudoran, Matthias Wollenhaupt, and Thomas Baumert — University of Kassel, Institute of Physics and Center of Interdisciplinary Nanostructure Science and Technology (CINSaT), D-34132 Kassel, Germany

Nonlinear label-free microscopy is a powerful tool for the investigation of physical and biological samples with high spatial resolution. Often intrinsic Second- or Third-Harmonic Generation as well as Coherent Anti-Stokes Raman Scattering is used as contrast mechanism.
We make use of fs pulse shaping in combination with self-phase modulation (SPM) in order to generate the nonlinear signals [1, 2]. Extending our previous studies [1], fs laser pulses are amplitude and phase modulated in a narrow spectral interval and focused into transparent samples. SPM leads to a redistribution of the power spectral density (PSD) depending on the nonlinear index of refraction. In particular the intensity of previously removed spectral components is recovered. Hence, observation of these intensities holds the possibility to distinguish between different materials. We demonstrate high nonlinear contrast within index matched photonic fibers combining the fs pulse shaping technique with a commercial laser-scanning-microscope. Moreover, the influence of additional spectral phases on the self-phase modulated PSD is studied and results are given.
[1] A. Präkelt et al.: Appl. Phys. Lett. 87(12), 121113(2005)
[2] M. C. Fischer et al.: Opt. Lett. 30(12), 1551(2005)