Dresden 2017 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 16: Layer Properties: Electrical, Optical, and Mechanical Properties I

DS 16.1: Vortrag

Montag, 20. März 2017, 17:00–17:15, CHE 91

On the depolarization in granular thin films: A systematic Mueller-Matrix approach. — •Bruno Gompf, Maximilian Gill, Martin Dressel, and Audrey Berrier — 1. Physikalisches Institut and Research Center SCoPE, Universität Stuttgart, Pfaffenwaldring 57, 70569 Stuttgart, Germany

Optical reflection or transmission measurements are usually described in the framework of Fresnel's equations, whereas the scattering of light on spherical particles is treated by Mie-theory. But what happens when strongly scattering dielectric Mie-particles form a thin film? To our eyes these granular films appear white. But how do they depolarize light? The polarization state of light is described by its Stokes vector, which can be visualized on a Poincare sphere. The interaction with the sample leads to a jump from one point of the Poincare sphere to another point (or area). Mueller-matrices allow a model-free description of this jump. Here we present systematic transmission and reflection Mueller-matrix ellipsometric measurements on strongly scattering granular BaSO4 thin films of different thicknesses. The depolarizing behavior is characterized via a comparative study of the respective differential-, product-, and sum-decomposition of the measured Mueller-matrices. The result of the different decompositions, together with the correlation effects reveals the underlying physical processes of depolarization.