Düsseldorf 2007 – wissenschaftliches Programm

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Q: Fachverband Quantenoptik und Photonik

Q 65: Poster Photonik

Q 65.6: Poster

Donnerstag, 22. März 2007, 16:30–18:30, Poster C

Talbot effect at two-dimensional microscopic periodic structures — •Ralf Ameling, Manuel Gonçalves, André Siegel, and Othmar Marti — Universität Ulm, Institut für Experimentelle Physik, D-89069 Ulm

The Talbot effect is a self-imaging phenomenon observable at periodic objects illuminated with coherent light. The intensity distribution at the grating is reproduced at distances that are mutiples of the Talbot distance. This lenght is dependent on the array symmetry, the lattice constant and the wavelength of the incident light.

We investigated self-imaging at two-dimensional hexagonal colloidal crystals consisting of polysterene spheres and their inverse egg-box-like structures. The observed diffraction patterns (especially at the Talbot-length) have been compared with computer simulations based on different theoretical models like the Rayleigh-Sommerfeld-theory and the Hertz-vector diffraction theory. In addition, several computer programs for the simulation of the propagation of electromagnetic waves and the optical near-field have been used to verify the results. They are based on the finite-difference time-domain (FDTD) algorithm and the finite element method .