In January 2021 we measured the set of nine reference materials for the material measurement comparison (EURAMET pilot study). From the complex transmission data and the previously determined specimen thickness values, the material parameters have been extracted via the standard method for all materials. In this standard method the Fresnel transmission coefficient equation is inverted to get the complex refractive index. From the complex refractive index all other material properties like the permittivity or the absorption coefficient can be determined.
First material parameter comparisons with available data from other partners have been carried out. From these comparisons, we see that there is a good general agreement between the different partners. However, for some materials like high-resistivity silicon, we should be able to get better results by applying other material parameter extraction methods or using some a priori knowledge of the optical properties.
Furthermore, we have managed the shipment of the set of reference materials and calibration artefacts between the different partners. METAS thereby serves as pivot institute since, due to customs reasons, all shipments start or end at METAS. In addition, we have acquired another partner that participates in the pilot study with a unique optical setup, namely a THz ellipsometer (group of Christian Bernhard, University of Fribourg).