Switchable broadband and wide-angular terahertz asymmetric transmission based on a hybrid metal-VO<sub>2</sub> metasurface
Xiaoxiang Dong, Xiaoqing Luo, Yixuan Zhou, Yuanfu Lu, Fangrong Hu, Xinlong Xu, Guangyuan Li
Abstract
We propose a switchable broadband and wide-angular terahertz asymmetric transmission based on a spiral metasurface composed of metal and VO 2 hybrid structures. Results show that asymmetric transmission reaching up to 15% can be switched on or off for circularly polarized terahertz waves when the phase of VO 2 transits from the insulting state to the conducting state or reversely. Strikingly, we find that relatively high asymmetric transmission above 10% can be maintained over a broad bandwidth of 2.6–4.0 THz and also over a large incident angular range of 0 ° –45 ° . We further discover that as the incident angle increases, the dominant chirality of the proposed metasurface with VO 2 in the conducting state can shift from intrinsic to extrinsic chirality. We expect this work will advance the engineering of switchable chiral metasurfaces and promote terahertz applications.