Rotation-Driven Multifunctional Metasurface for Holography Encryption

Metasurfaces enable versatile wavefront control, but passive designs struggle with multichannel dynamic switching, while active approaches often introduce complexity and require external power. Here, we propose a rotation-driven multifunctional metasurface holographic encryption scheme based on a cascaded architecture of two single-layer dielectric metasurfaces. By mechanically rotating one metasurface relative to the other, dynamic switching of holographic images across multiple predefined focal planes is achieved without any external energy supply. The encryption information is encoded into a multidimensional key space, defined by three independently controllable physical dimensions: rotation angle (4 states), incident polarization (3 states), and imaging distance (3 states), offering up to 36 theoretical key combinations. These parameters constitute distinct and independently controllable dimensions within the key space, substantially enhancing resistance to unauthorized access. As a proof-of-concept demonstration, full-wave simulations confirm faithful reconstruction of four independent images under four representative key combinations at a fixed operating frequency. This passive, mechanically reconfigurable approach offers a practical and secure pathway for three-dimensional dynamic displays and holographic encryption, with obvious advantages in simplicity, cost, and integrability over active tuning methods.