Berlin 2015 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 15: P1: Interfaces and Thin Films
CPP 15.7: Poster
Monday, March 16, 2015, 16:00–19:00, Poster A
Accurate Refractive-Index Determination from First- and Second-Order Critical Angles of Periodic Surface Patterns — •Christoph Meichner1, Lothar Kador1, Andreas Schedl2, Hans-Werner Schmidt2, Christian Neuber2, and Klaus Kreger2 — 1University of Bayreuth, Institute of Physics and Bayreuth Institute of Macromolecular Research (BIMF), 95440 Bayreuth, Germany — 2University of Bayreuth, Macromolecular Chemistry I and Bayreuth Institute of Macromolecular Research (BIMF), 95440 Bayreuth, Germany
We present a novel method for the determination of the refractive-index dispersion of transparent solid films. The approach is based on irradiating collimated monochromatic light onto the sample with the illuminated spot carrying a periodic surface pattern. A simple rotational stage is sufficient for measuring critical angles of the light propagating in the film. From these angles, the refractive indices are calculated. To study the accuracy of our method, we prepared samples of a PDMS cast resin (Sylgard® 184) and compared the results to those obtained with an Abbe refractometer. The data are in good agreement, considering the angular resolution of the stage and the precision of the grating constant.