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DD: Didaktik der Physik

DD 26: Postersitzung

DD 26.2: Poster

Dienstag, 19. März 2002, 13:30–15:30, Galerie 1

Electro-optic characterization of DR1 doped PMMA films by use of waveguide sample geometry. — •Dimitrios Anestopoulos, Vassilios Giannetas, Petros Persefonis, and Dimitrios Zevgolis — Physics Department, University of Patras, GR 26500 Patras

The linear electro-optical coefficients r33 and r13 of a strongly nonlinear organic chromophore, DR1 in PMMA solid matrix, were measured via a technique based on a waveguide sample geometry. The technique used is simple and accurate and the interpretation is straight forward. Viscous solutions of DR1 and PMMA were prepared in chlorophorm and films were made from these solutions by casting onto metallic (Al) substrates. The polymeric surfaces of two substrates were pressed together to from a sandwich. A DC poling electric field was applied to the metallic substrates (acting as electrodes). A He-Ne laser beam, polarized at 45o with respect to the poling direction, in transmitted through the DR1/PMMA film. A polarizer placed in front of a photodiode was used to determine the polarization state of the beam. The relation between the electro-optical coefficients r33 and r13 (|r33-r13|) was calculated via the induced birefringence Dn. The results indicate a strong nonlinearity, which remains constant for a significant period of time. The birefringence and the electro-optical coefficients observed were of the order 10-5 and 10pm/V respectively. Similar results were obtained from films of various concentrations of DR1 in PMMA.