Resolution limits due to ellipticity in submicron photoalignment with Berry-phase photomasks

Abstract Photoalignment using Berry-phase masks enables single-step transfer of complex liquid crystal (LC) patterns but faces difficulty in reproducing submicrometer patterns. In this study, the physical limitation using Berry-phase masks is elucidated through combined simulations and experiments. Finite-difference time-domain analysis reveals that transmitted light evolves into elliptically polarized states as the mask period decreases, and experimental evaluation confirms that ellipticity significantly weakens anchoring strength. In addition, a multilayer Berry-phase mask design is proposed to suppress polarization ellipticity. This approach clarifies the origin of alignment disorder and advances the mass production of high-resolution LC meta-optics and augmented reality/virtual reality photonic devices.