Programmable Metasurface for Amplitude‐Phase‐Independent Microwave Meta‐Printing and Synchronous Holography in Information Encryption

ABSTRACT In recent years, multi‐channel multiplexed information encryption based on nanoprinting and holography has been extensively studied. Metasurfaces, owing to their exceptional capability for precise electromagnetic wave manipulation, have shown great potential in fields such as encryption and imaging. However, current optical metasurface‐based nanoprinting rely primarily on amplitude modulation governed by Malus's law and are limited by the inflexible control of meta‐atoms, thereby restricting information capacity enhancement to a finite increase in the number of channels. Here, a phase‐modulated microwave meta‐printing approach is proposed, which enables pixel‐level image construction in the near‐field phase dimension via precise phase control of each meta‐atom. To achieve this, in the microwave regime, we develop a transmissive polarization‐conversion information‐encoding metasurface that supports independent modulation of both amplitude and phase. By integrating conventional holography, a dynamic encryption‐imaging platform is constructed that enables synchronous near‐field independent phase‐based and amplitude‐based meta‐printing, as well as synchronous near‐field meta‐printing and Fresnel holographic imaging. The encryption platform leverages the novel imaging modality of near‐field phase‐based meta‐printing to establish an instruction verification mechanism. Combined with a six‐dimensional key, this approach creates a secure channel for information transmission, offering a new paradigm for secure electromagnetic wave communication and information hiding.