Ellipsometry measures variations of the polarization state of light reflected from a surface. Optical constants (n and k) or the dielectric function (ε’ and ε’’) of the substrates and layers as well as layer thickness can be determined. In our lab spectroscopic and imaging ellipsometry in the visible spectral range are used to characterize thin layers (mainly polymers) on solid substrates. Key aspects of our work are:

1. In-situ measurements in air/N2 and liquids (as function of time, temperature, composition, pH..), e.g. swelling/deswelling, adsorption/desorption, thermal expansion, in combination with quartz crystal microbalance (QCM-D).
2. Determination of the orientation of dipol transition moments in anisotropic light absorbing thin organic films.  

For a survey of textbooks on the method ellipsometry, please have a look at the website of the “Arbeitskreis Ellipsometrie (AKE) – Paul-Drude e.V.”: "http://www.ake-pdv.org/index.php/ellipsometry"