Polarization‐Insensitive VO 2 /Graphene/Diamond Heterostructure Metasurface With Dynamic Broadband/Narrowband Tunability
Boning Wen, Feng Wen, Shaowei Zhang, Muhua Zhai, Xin Yao, Chengyong Wang, Yang Lei, Zepei Li, Jiani Li, Zhihao Tong, Yanpeng Zhang, Hongxing WangABSTRACT
Multifunctional metasurfaces, a type of artificial two‐dimensional material, enable simultaneous or switchable modulation of electromagnetic radiation's multiple degrees of freedom through elaborate subwavelength periodic/aperiodic structure design, with applications in communications, imaging, and sensing. However, existing ones face difficulties in precisely modulating narrowband/broadband modes, both limited by low Q‐factors. Here, we present a polarization‐insensitive multifunctional switchable metasurface enabled by a vanadium dioxide (VO 2 )/graphene/diamond heterostructure. We demonstrate that flexible switching of the metasurface between narrowband and broadband modes can be achieved by precisely tuning the Fermi level of the upper graphene layer and the electrical conductivity of the lower VO 2 . The Q‐factors of two narrowband peaks reach 32.7 and 41.9, which are significantly higher than previously reported values. Furthermore, tailoring the gap between adjacent graphene disks can facilitate the achievement of BIC and quasi‐BIC within the system. In addition, we also demonstrate that systematic optimization of key parameters, including geometric structure, chemical potential, and carrier relaxation time, enables the multifunctional metasurface to achieve robust impedance matching with free space, coupled with a large angular tolerance and remarkable polarization insensitivity. This multifunctional metasurface holds considerable potential for applications in spectral sensing, terahertz filtering, and electromagnetic interference (EMI) shielding devices.