Recently, a research team headed by Professor Si Liming of the School of Integrated Circuits and Electronics at Beijing Institute of Technology, in conjunction with Professor Yang Fan from Tsinghua University and Associate Professor Zhu Weiren, a tenured associate professor at Shanghai Jiao Tong University, has made remarkable strides in the realms of microwave three-dimensional (3D) holographic imaging and multi-channel information encryption. Their pertinent research outcomes have been featured in the IEEE Transactions on Antennas and Propagation, a premier journal in the international antennas and propagation sector, with the publication of two papers: "Asymmetric 3D Holographic Imaging Using Complex-Amplitude Janus Metasurface" and "Multi-Channel Orbital Angular Momentum Encryption Holography Based on Complex-Amplitude Janus Metasurface."

This research overcomes the constraints of conventional metasurfaces, which mainly depend on amplitude and phase within a two-dimensional plane for information encoding. It does so by incorporating the propagation direction and distance as extra dimensions for information encoding, thereby substantially boosting the flexibility in electromagnetic information manipulation. By introducing the orbital angular momentum (OAM) topological charge as a novel information dimension, the research team has successfully implemented the collaborative multiplexing of multiple electromagnetic degrees of freedom, encompassing propagation direction, propagation distance, and OAM modes. This advancement paves the way for innovative approaches in multi-dimensional electromagnetic information encoding, computation, transmission, storage, communication, sensing, and security.

The research findings are anticipated to be instrumental in areas such as high-security holographic encryption, high-density information storage, space-division multiplexing wireless communications, cutting-edge electromagnetic displays, and cyber-physical systems.