A synchrotron-radiation-based variable angle ellipsometer for the visible to vacuum ultraviolet spectral range.

Area of Science:

• Optics and Photonics
• Materials Science
• Metrology

Background:

• Ellipsometry is a powerful technique for characterizing optical properties of materials.
• Broad energy range spectroscopic ellipsometry is crucial for advanced material analysis.
• Vacuum ultraviolet (VUV) spectral range presents challenges for polarization control.

Purpose of the Study:

• To present a novel rotating analyzer spectroscopic polarimeter and ellipsometer (RASPE) with a wide energy range.
• To introduce a new compensator design for VUV ellipsometry.
• To demonstrate the instrument's capability in characterizing materials and beamline polarization.

Main Methods:

• Installation of a RASPE with a wide-range θ-2θ goniometer at the Metrology Light Source.
• Utilizing transmission- and reflection-based polarizing elements and undulator radiation.
• Development and implementation of a CaF2 Fresnel rhomb compensator for VUV measurements.

Main Results:

• The ellipsometer covers photon energies from 2 eV to 40 eV.
• The CaF2 Fresnel rhomb compensator enables circular polarization measurements in the VUV range.
• Initial characterization of beamline polarization and dielectric function of ZnO were successfully performed.

Conclusions:

• The developed RASPE is a versatile instrument for broad energy range spectroscopic ellipsometry.
• The new VUV compensator expands the capabilities for analyzing depolarizing samples.
• The instrument is suitable for precise metrology and material characterization, as demonstrated by ZnO analysis.