Asynchronously Tunable Persistent Luminescence and Photochromism in SrGa ₂ O ₄ : Dy ³⁺ , Zn ²⁺ for Dual‐Level Data Storage and Self‐Locking Information Encoding

High‐density optical storage represents a critical solution to the multifaceted issues confronting big data storage. Persistent luminescence/photochromism (PersL/PC) dual‐mode materials have the potential to enhance optical storage capacity through mode multiplexing. However, strategies to achieve this goal through asynchronous regulation of dual‐mode information have not been established. This study synthesized the dual‐mode phosphor SrGa 2 O 4 : Dy 3+ , Zn 2+ (SGO: Dy 3+ , Zn 2+ ), which shows white PersL (0.32 mcd/m 2 > 4500 s) and brown PC (ΔR cmax = 62.27%) under 254 nm UV LED irradiation. Fortunately, 808 nm laser selectively quenches its PersL while preserving PC performance, thereby achieving asynchronous regulation of dual‐mode information. Mechanistic investigation reveals that the behavior stems from the well‐differentiated depth distributions of the function‐specific traps. The sample also successfully demonstrates the desired mode‐multiplexing data storage and advanced self‐locking encryption applications. Therefore, this study pioneers an innovative strategy for high‐density optical storage and advanced encryption, while providing feasible insights into material design principles.