极化(电化学)
波前
拓扑(电路)
物理
光学
材料科学
光电子学
化学
数学
组合数学
物理化学
作者
HU Shi-sheng,Chao Wang,Shuo Du,Zhonghua Han,Changzhi Gu
出处
期刊:Nano Letters
[American Chemical Society]
日期:2024-02-01
标识
DOI:10.1021/acs.nanolett.3c04621
摘要
Exceptional points (EPs), known as non-Hermitian singularities, have been observed and investigated in parity-time symmetric metasurfaces. However, the chirality and tunability in non-Hermitian metasurfaces still need to be explored. Here, we propose a dynamic topological metasurface with the meta-atom consisting of two orthogonally oriented nanorods, which are placed on the phase change material Ge2Sb2Te5 (GST) and SiO2 dielectric layer, respectively. When GST is converted from the amorphous state (a-GST) to the crystalline state (c-GST), an EP can be dynamically switched from the “ON” state to the “OFF” state in a parameter space. Moreover, based on the topologically protected phase and amplitude modulations of the cross-polarization component, the phase-only hologram and amplitude-only hologram are engineered in the a-GST case and concealed in the c-GST case. Finally, we explore the 2D-chiral symmetry of meta-atoms and further propose two spin-selective meta-deflectors and a hybrid meta-deflector operating with arbitrary polarizations. The GST-based hybrid metasurface offers richer possibilities to realize various wavefront controls.
科研通智能强力驱动
Strongly Powered by AbleSci AI