Spectro-Ellipsometric Surface Plasmon Resonance Sensor Using a Liquid Crystal Achromatic Waveplate

Wavelength dependence of phase modulators has been one of the main challenges in spectroscopic ellipsometry/polarimetry (EP) which significantly complicates signals analysis. A known approach to overcome this complication is using rotatable polarizers. However, the use of rotatable polarizers induces mechanical vibrations and unnecessary errors to the system. In this work, a novel spectroscopic configuration to extract the spectral changes of the EP parameters applied to surface plasmon resonance (SPR) sensing is presented. The setup utilizes the integration of a recently developed achromatic variable liquid crystal waveplate to the SPR in Kretschmann-Raether configuration and using three phase shifts to extract the EP parameters of the SPR sample.