Berlin 2005 – scientific programme

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AKB: Biologische Physik

AKB 100: Poster Session I

AKB 100.53: Poster

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

Near-field Electrodynamics of Biological Cells — •Kort Travis and Jochen Guck — Universität Leipzig, Fakultät für Physik und Geowissenschaften, Abteilung Physik der weichen Materie, Linnéstrasse 5, 04103 Leipzig, Germany

Understanding near-field interactions of coherent infrared light with biological cells is critically important for modern optical manipulation and trapping applications, such as the Optical Stretcher or the Optical Tweezers. With respect to classical scattering theory, considerations of refractive index and size classify cells in the “anomalous diffraction” regime. For this regime, the near-fields are best analyzed using exact approaches such as Mie theory, or the system transfer operator (T-matrix) formalism. In the present discussion, T-matrix formalism is used to evaluate general features of optical fields in and around cells. Specifically, the discussion will cover: electrodynamic characteristics of all objects in this optical size range; effects of surface deviations from ideal shape; effects of the inclusion of large organelles such as the nucleus; and finally, effects associated with local inhomogeneities in the refractive index. Key points in the analytical discussion are illustrated with examples from numerical simulation and from experimental results.