Terahertz Nonvolatile Vectorial Holography With Random Repetitive Encryption and Nonreciprocal Janus Imaging Based on Magnetic Heterogeneous Integrated Metasurface
Hao Wang, Fei Fan, Pengxuan Li, Qiang Xue, Zhiyu Tan, Dan Zhao, Huijun Zhao, Qinghui Yang, Qiye Wen, Shengjiang Chang
Abstract
Abstract Vectorial holography expands the information dimensionalities of the image, manifesting significant value in applications such as optical encryption, and polarization multiplexing. To address challenges like erasable storage, secret key leakage, and echo noise, a dynamic terahertz vectorial holography is demonstrated based on magnetic heterogeneous integrated metasurfaces with nonvolatility and nonreciprocity, whose polarization states vary continuously along the latitude of the whole Poincare Sphere with the experimental polarization ellipticity angles in the image covering −0.23π–0.21π rad, and can be stored or erased through nonvolatile magnetic rotation. This allows for the encryption with a random dynamic polarization secret key that can be regenerated indefinitely, greatly eliminating the risk of key leakage. The crosstalk between the orthogonal polarization states in the encryption is less than 0.0056. Meanwhile, leveraging the magneto‐optical nonreciprocity, the metasurface functions as a Janus hologram with one‐way isolation between forward and backward illumination, of which the image area proportion of over 5 dB isolation reaches 89%, effectively eliminating echo noise and further improving the anti‐interference. This work addresses the gaps in terahertz dynamic vectorial holography, realizes the nonvolatile and nonreciprocal polarization information processing, and mitigates risks of secret key leakage and echo interference.