Dresden 2006 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
DY: Dynamik und Statistische Physik
DY 46: Poster
DY 46.7: Poster
Donnerstag, 30. März 2006, 16:00–18:00, P1
Experimental verification of a new scattering model for Total Internal Reflection Microscopy — •Christopher Hertlein1, Laurent Helden1, Elena Eremina2, Thomas Wriedt2, and Clemens Bechinger1 — 12. Phys. Institut, Universität Stuttgart, Pfaffenwaldring 57, 70550 Stuttgart — 2Institut für Werkstofftechnik, Universität Bremen, Badgasteiner Str. 3, 28359 Bremen
Total Internal Reflection Microscopy (TIRM) is a method for precise measurements of colloid - wall interaction potentials based on single particle evanescent wave light scattering. The technique is capable of resolving forces in the femtonewton range. In an evanescent field the scattering intensity strongly depends on the particle wall distance. The well established model used to interpret TIRM data is based on a simple exponential relation between intensity and distance. We developed a new model, that for the first time takes into account the exact experimental parameters. This model shows strong deviations from a purely exponential dependency of intensity and distance for certain parameters. These deviations can lead to severe artefacts in the measured interaction potentials. Using a TIRM-setup based on single-photon counting, we verified the dependency of the artefacts on experimental parameters such as average particle wall distance, penetration depth and polarisation of the evanescent wave.