Full‐Space Switchable Transmissive‐Reflective Metasurface Nano‐Printing in Real‐Space and Holography in k ‐Space

ABSTRACT Metasurfaces represent a class of artificially engineered planar optical devices that achieve exceptional functional performance through optimized nanostructure design and array configurations. These devices have emerged as the predominant methodology for developing integrated, compact optical systems, offering micro‐ and nano‐scale solutions that enable comprehensive multidimensional optical modulation. Here, we report a full‐space switchable optical encryption platform exhibiting wavelength‐dependent information control. Through precisely engineered nanostructures, the system demonstrates three distinct operational regimes: selective reflection revelation without transmission, complete concealment of real‐space information via dual‐holographic encryption, and switchable recovery of both real‐ and k ‐space manifestations across transmission and reflection modes. Spectroscopic characterization and computational modeling reveal the critical role of dielectric nanopillar resonance in enabling these switchable states. This work establishes a paradigm for active optical security devices with potential applications in anti‐counterfeiting, optical communication, switching, and information encryption technologies.