Dispersion-engineered compact twisted metasurfaces enabling 3D frequency-reconfigurable holography

Flexible dispersion manipulation is critical for holography to achieve broadband imaging or frequency division multiplexing. Within this context, metasurface-based holography offers advanced dispersion control, Yet dynamic reconfigurability remains largely unexplored. This work develops a dispersion-engineered inverse design framework that enables 3D multi-plane frequency-reconfigurable holography through a twisted metasurface system. The physical implementation is based on a compact bilayer configuration that cascades the broadband radiation-type metasurface (RA-M) and phase-only metasurface (P-M). The RA-M provides a phase-adjustable input to excite P-M, while the rotation of P-M creates a reconfigurable response of holograms. By employing the proposed scheme, dynamic switching of space-frequency multiplexing and achromatic holograms is designed and experimentally demonstrated in the microwave region. This method advances flexible dispersion engineering for metasurface-based holography, and the compact system holds significant potential for applications in near-field computational imaging/detection, high-speed high-data-capacity near-field wireless communication, and switchable meta-devices.