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BP: Fachverband Biologische Physik

BP 28: Posters: Imaging

BP 28.9: Poster

Thursday, March 29, 2012, 17:30–19:30, Poster A

Interferometric Particle Tracking — •Dennis Müller and Rainer G. Ulbrich — IV. Physikalisches Institut, Georg-August-Universität Göttingen, Germany

We report interferometric tracking of gold nanoparticles with spatial resolution in the nanometer range and sub-millisecond temporal resolution. This technique combines a dark-field microscope with laser illumination with a Mach-Zehnder-like interferometer which follows the camera exit of the microscope. In the interferometer scattered light from the object particle is superimposed with scattered light from a reference particle which has been immobilized in the object plane. Readout is done by avalanche photodiodes. The phase of the resulting interferogram is a very sensitive measure for displacements of the object particle relative to the reference particle. This configuration eliminates effectively the effect of microscope drift on the measurement and makes this technique a promising candidate for applications like motor protein tracking experiments.