Far-infrared ellipsometry using a synchrotron light source—the dielectric response of the cuprate high Tc superconductors

We describe the setup of an ellipsometer for the far- to mid-infrared (FIR-MIR) spectral range that is used in combination with a Fourier-transform infrared (FTIR) spectrometer and a synchrotron light source.We present the outline of the ellipsometer and discuss how it has been optimized in order to perform accurate ellipsometric measurements on relatively small single crystals of the cuprate high-T superconductors (HTSC) and other oxide based compounds with strongly correlated charge carriers. We present ellipsometric spectra for the HTSC compounds BiSrCaCuO and YBaCuO.