Heterogeneous Polymer Multilayers Enabling Photoresponsive Nonreciprocal Patterns for Information Encryption

Abstract Society has a growing demand for information security. The development of nonreciprocal patterns is a new approach for high‐security information encryption, but it is difficult to achieve due to its complexity in material design. Herein, heterogeneous polymer multilayers are designed to prepare nonreciprocal patterns for information encryption. The heterogeneous polymer multilayers are constructed by gluing polyvinyl alcohol (PVA) polarizers and photoresponsive azobenzene‐containing polymers (azopolymers) via photocontrolled adhesion. Nonreciprocal optical patterns are fabricated via photopatterning of the azopolymer layer with polarized light. The information can only be decrypted from one direction of the nonreciprocal optical patterns. The nonreciprocal optical patterns are dynamic, which can be erased and rewritten with updated information via light irradiation. The nonreciprocal optical patterns can be further imprinted with diffraction elements, showing dual‐mode optical signals. The nonreciprocal optical patterns with dynamic, dual‐mode features enable high‐security information encryption. Moreover, the heterogeneous polymer multilayers are flexible, bendable, and foldable, enabling the design of devices with nonreciprocal optical patterns for encryption in 3D space. The heterogeneous polymer multilayers with photoresponsive nonreciprocal patterns offer a solution for designing secure, updatable, and mechanically robust information encryption materials for flexible photonics, portable electronics, new anti‐counterfeiting technologies, and wearable devices.