UV-Polarizers for wavelengths from 150 to 250 nm based on exciton generation in dielectric materials (PolEx)

• Applicant: Professorin Dr. Stefanie Kroker
• Subject Area: Synthesis and Properties of Functional Materials
• Term: from 2016 to 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 287542364

The vacuum ultraviolet (VUV) spectral range plays a major role in optical imaging and analytical applications such as lithography, spectroscopy and ellipsometry. Thereby, the polarization control of light enables enhanced imaging quality and provides valuable information about material properties down to atomic scale. Compact, integrable optical polarizers with scalability to large areas and robustness towards misalignment would strongly promote advances to miniaturized VUV instruments. For instance, such devices can be of interest in satellite remote sensing. Conventional metal wire grid polarizers are commonly used in the visible and infrared spectral range. However, they increasingly fail at wavelengths smaller than 250 nm and thus also in the VUV. In this project we aim to drive the application limits of such nano-optical polarizers down to 150 nm. For this purpose, we propose and develop grating polarizers based on the generation of excitons in artificial dielectric media. In order to design these elements, spectrally tailored bandgap materials will be of great advantage. Beside fundamental studies on materials the research focus will be the development of novel segmented grating structures. By segmentation we aim for the realization of polarizers with unprecedented multi-spectral function. The elements experimentally realized in this project are expected to provide a performance up to now exclusively available for wire grid polarizers in the VIS and IR spectral region. Due to their broadband behavior und robustness towards misalignment they will be of high benefit in compact VUV ellipsometers and polarization resolved imaging systems.

• DFG Programme: Research Grants