Full-Phase Parameter Modulation with Arbitrary Polarization Combination via Bidirectional Asymmetric Transmission Meta-Devices

The bidirectional asymmetric transmission (BAT) meta-devices have attracted widespread attention as an emerging display, encryption, and information storage platform. Generally, the multiplexing capability of BAT meta-devices determines the upper limit of the loading capacity of multi-task integrated systems. However, existing BAT meta-devices still depend on structural properties and the arrangement of meta-atoms, limiting the number of manipulated channels, operating frequency, and polarization combinations. Herein, a universal BAT meta-device, enabling bidirectional eight-phase-channel asymmetric transmission, composed of bilayer spatially cascaded birefringent metasurfaces (BMs) is proposed to allow for arbitrary polarization combination via the inverse design method and validated in the microwave region. In addition, the polarization multiplexing capabilities of BAT meta-devices are further extended via a Lego-like physical mechanism. The proposed design strategy may facilitate BAT meta-devices functional innovation and advanced application deployment in holographic images, duplex communication, and secret-key-sharing data encryption.