Polarizing interferometer for the unambiguous determination of the ellipsometric parameters

We report on a polarizing interferometer-ellipsometer arrangement that overcomes the need for additional measurements with a retarder for the unambiguous determination of the ellipsometric parameters in the far infrared spectral range. It consists of a Martin-Puplett interferometer and a wire-grid polarizer as an analyzer. The application of such interferometer-ellipsometer is experimentally demonstrated on a polyethylene sample deriving the refractive index and the thickness in the spectral range between 15 and 35 cm 1. Based on these results, a similar solution without a retarder for the mid-infrared spectral region is additionally proposed. Published by The Optical Society under the terms of the Creative Commons Attribution 4.0 License.