46‐Channel Image Encryption Based on Optically Controlled Metasurfaces

Abstract With the rapid growth of data volumes in modern society, efficient and secure methods for information transmission, storage, and encryption have become essential. Benefiting from high‐density storage and fast access to 2D data, optical encryption shows significant promise for data protection. Metasurfaces, as a type of 2D artificial metamaterials capable of precisely controlling electromagnetic waves, have greatly advanced the development of multi‐channel optical encryption. However, many existing metasurface‐based optical encryption devices are limited by static operation and stringent requirements on materials or light sources. Here, a 46‐channel image encryption device is proposed, integrated with optically controlled metasurfaces to achieve dynamically tunable and high‐capacity optical encryption. An efficient binary amplitude‐phase inverse‐design method is developed that enables high performance optical encryption by incorporating binary amplitude distributions into an isotropic phase metasurface. This approach imposes minimal additional requirements on the light source or the metasurface. Experimental demonstrations using an infrared‐pump/terahertz‐probe imaging system confirm the effectiveness and robustness of the encryption device, highlighting its potential for advanced and flexible optical encryption applications.