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Abstract Photonic crystals (PCs) are innovative structures with periodic variations in refractive index, enabling remarkable light manipulation capabilities that hold promise for fundamental research and practical applications in physics, biology, and engineering. This work explores the hierarchical structures of blue‐phase liquid crystals (BPLCs), which are characterized by distinct omnidirectional photonic band gaps. By leveraging the asymmetric domain growth of BP a novel method for bistable information hiding and revealing is proposed. With a single‐side photopatterned cell, a polydomain of BPLC is formed during cooling thanks to the generated temperature gradient. Upon applying an alternating current (AC) electric field, a monodomain state is achieved, allowing for clear, high‐contrast information retrieval. Both quick response (QR) code and geometric phase hologram are encoded to the alignment layer, and reversible information hiding and revealing are demonstrated via alternating the heating and electric driving processes. Moreover, continuous shifting of reflective color is presented via varying applied voltages. The proposed technique may inspire future applications in optical encryption, camouflage, and advanced information security technologies.
Chen et al. (Tue,) studied this question.