A numerical study on a voltage-tunable quasi-broadband depolarizer enabled by periodic protrusion-induced liquid crystal reorientation

초록

Depolarizers are essential for suppressing polarization-dependent artifacts, yet conventional designs are limited by their static performance. We propose a structurally simple liquid-crystal (LC) depolarizer achieving electrically tunable performance via a periodic micro-protrusion array. These protrusions locally inhibit LC reorientation under voltage, naturally generating spatial variations in both optic-axis orientation and phase retardation—two fundamental requirements for depolarization identified by Poincaré-sphere analysis. Although single LC layers typically lack broadband characteristics, our device enables any wavelength within the 200–2000 nm range to reach a near-zero degree of polarization (DoP) at an optimized voltage, functioning as a quasi-broadband depolarizer. Numerical simulations confirm that intermediate voltages produce rich spatial birefringence profiles and voltage-dependent DoP minima. This proposed structure offers a compact, electrically reconfigurable solution for imaging, sensing, and spectroscopy, providing a versatile platform for polarization-insensitive optical systems.

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