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MO: Fachverband Molekülphysik

MO 18: Experimental Techniques

MO 18.4: Vortrag

Mittwoch, 20. März 2013, 14:45–15:00, F 102

Biological samples imaged by multimodal nonlinear microscopy with 10fs pulses. — Jean Rehbinder, •Lukas Brückner, Tiago Buckup, and Marcus Motzkus — Physikalisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, D-69120 Heidelberg, Germany

In Multimodal Nonlinear Optical Microscopy (NLOM), several multiphoton signals are detected simultaneously providing complementary, label-free contrast mechanisms based on chemical and structural properties of the sample. Usually, pulses with durations down to 100fs are used. In this work, imaging with 10fs NIR pulses is demonstrated. A 10 fold increase in two-photon signals is predicted and 100 fold for three-photon effects. Such broadband pulses are strongly affected by the big amount of dispersion introduced by microscope objectives. A pulse shaper is used to compensate arbitrary phase distortions. Once the pulse is compressed, the shaper can be used to tailor it with high flexibility and increase contrast and selectivity of the excitation. These advantages are illustrated using Second Harmonic Generation (SHG) in combination with Two-Photon Excited Fluorescence (TPEF) and Coherent Anti-Stokes Raman Scattering (CARS) for imaging of skin biopsies. Phase and amplitude shaping schemes are demonstrated on the basis of moss leaves using CARS and TPEF. Polarization control gives access to the tensorial nature of given nonlinear effects. The potential to determine orientation of collagen fibrils in a tendon from a rat-tail is shown and illustrates the versatility of pulse shaping for nonlinear microscopy.