Benwen Chen, Shengxin Yang, Jian Chen, Jingbo Wu, Ke Chen, Weili Li, Yihui Tan, Zhaosong Wang, Hongsong Qiu, Kebin Fan, Caihong Zhang, Huabing Wang, Yijun Feng, Yunbin He, Biaobing Jin, Xinglong Wu, Jian Chen & Peiheng Wu
Chen et al. (2023)
Light: Science & Applications 12, 136
Research overview
This paper demonstrates thermally reconfigurable terahertz Janus metasurfaces, devices that respond differently to THz waves arriving from opposite directions. By integrating the phase-change material vanadium dioxide (VO2) into the meta-atoms, the authors obtain asymmetric transmission with designed phase delays that switch when VO2 undergoes its insulator–metal transition on heating. Incidence direction and temperature therefore act as independent keys, giving four separate functionalities from a single metasurface. Working around 1 THz, the team demonstrated an asymmetric, varifocal meta-lens and directional holography that projects four independent images. Measurements used a THz spectral imaging system with a wire-grid polarizer to define the incident polarization. Potential applications include THz information encryption, data storage and smart windows.
Key findings
- VO2-integrated Janus metasurfaces with direction-dependent, thermally switchable THz response
- Four independent functionalities from one device, keyed by incidence direction and temperature
- Asymmetric meta-lens and directional four-image holography demonstrated around 1 THz
- Potential uses in THz information encryption, data storage and smart windows
