Tunable vector vortex beam generation using phase change metasurfaces [Invited]  

作　　者：Xinyi Ding Zerong Li Jiahui Ren Ziwei Zheng Fei Ding Shiwei Tang 丁歆怡;李泽榕;任家辉;郑紫微;丁飞;汤世伟(School of Physical Science and Technology,Ningbo University,Ningbo 315211,China;Digital Industry Research Institute,Zhejiang Wanli University,Ningbo 315100,China;Centre for Nano Optics,University of Southern Denmark,DK-5230 Odense M,Denmark)

机构地区：[1]School of Physical Science and Technology,Ningbo University,Ningbo 315211,China [2]Digital Industry Research Institute,Zhejiang Wanli University,Ningbo 315100,China [3]Centre for Nano Optics,University of Southern Denmark,DK-5230 Odense M,Denmark

出　　处：《Chinese Optics Letters》2024年第11期146-151,共6页中国光学快报(英文版)

基　　金：supported by the Natural Science Foundation of Zhejiang Province (No.LY24A040001);the Ningbo Youth Science and Technology Innovation Leading Talent Project (No.2023QL001);the Villum Fonden (No.37372);the Danmarks Frie Forskningsfond (No.1134-00010B);the Fundamental Research Funds of Shaanxi Key Laboratory of Artificially Structured Functional Materials and Devices。

摘　　要：Vector vortex beams(VVBs), novel structured optical fields that combine the polarization properties of vector beams and phase characteristics of vortex beams, have garnered widespread attention in the photonics community. Capitalizing on recently developed metasurfaces, miniaturized VVB generators with advanced properties have been implemented. However,metasurface-empowered VVB generators remain static and can only generate one pre-designed structured light. Here, we propose a kind of phase change metasurface for tunable vector beam generation by utilizing anisotropic Ge2Sb2Se4Te1(GSST) unit cells with tunable phase retardation when GSST transits between two different phase states. By properly rotating the orientations of the tunable GSST unit structures that transit between quarter-wave plates and half-wave plates, we can effectively transform incident plane waves into vector beams with distinct topological charges and polarization states.When GSST is in the amorphous state, the designed metasurface can transmit circularly polarized light into VVBs. In the crystalline state, the same GSST metasurface converts linearly polarized light into second-order radially polarized(RP) and azimuthally polarized(AP) beams. Our phase-change metasurface paves the way for precise control over the polarization patterns and vortex characteristics of beams, thereby enabling the exact manipulation of beam structures through the alteration of their phase states.

关 键 词：tunable metasurface wavefront manipulation vector vortex beam. 

分 类 号：O43[机械工程—光学工程]