Electrically Tunable GHLC Polarization Filter for Adaptive Contrast Enhancement in Imaging Sensors

초록

We report an electrically tunable polarization filter based on a guest-host liquid crystal system for real-time adaptive imaging in sensor applications. The device operates in three distinct optical states-transparent, s-polarized absorption, and p-polarized absorption-enabling dynamic control of light transmission depending on lighting conditions. By incorporating high-birefringence, negative dielectric liquid crystals and dichroic dyes, and using horizontal and vertical field control, the filter achieves efficient polarization-selective modulation without mechanical components. Both horizontal and vertical electric fields were employed to realize homeotropic, planar, and twisted molecular alignments. The resulting changes in tilt and twist angle distributions were evaluated through numerical simulations, and the optical response was experimentally validated using outdoor imaging scenarios. The device demonstrates polarization-dependent light attenuation with a DoLP of up to similar to 0.6, providing enhanced visibility and contrast depending on glare conditions and viewing angles. This compact and low-power structure functions as an electrically reconfigurable optical interface, suitable for glare suppression and contrast enhancement in smart camera modules, surveillance systems, and autonomous sensing platforms.

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