If a metalens integrates the circular polarization (CP) conversion function, the focusing lens together with circular-polariz-ing lens (CPL) in traditional cameras may be replaced by a metalens. However, in terahertz (THz) band, the reported metalenses still do not obtain the perfect and strict single-handed CP, because they were constructed via Pancharatnam-Berry phase so that CP conversion contained both left-handed CP (LCP) and right-handed CP (RCP) components. In this paper, a silicon based THz metalens is constructed using dynamic phase to obtain single-handed CP conversion. Also, we can rotate the whole metalens at a certain angle to control the conversion of multi-polarization states, which can simply manipulate the focusing for incident linear polarization (LP) THz wave in three polarization conversion states, in-cluding LP without conversion, LCP and RCP. Moreover, the polarization conversion behavior is reversible, that is, the THz metalens can convert not only the LP into arbitrary single-handed CP, but also the LCP and RCP into two perpen-dicular LP, respectively. The metalens is expected to be used in advanced THz camera, as a great candidate for tradi-tional CPL and focusing lens group, and also shows potential application in polarization imaging with discriminating LCP and RCP.

Key Laboratory of Opto-Electronics Information Technology(Tianjin University),Ministry of Education,School of Precision Instruments and Opto-Electronics Engineering,Tianjin University,Tianjin 300072,China;Beijing Engineering Research Center for Mixed Reality and Advanced Display,School of Optics and Photonics,Beijing Institute of Technology,Beijing 100081,China;Beijing Key Laboratory for Metamaterials and Devices,Key Laboratory of Terahertz Optoelectronics,Ministry of Education,and Beijing Advanced Innovation Center for Imaging Technology,Department of Physics,Capital Normal University,Beijing 100048,China

[1]Jitao Li;Guocui Wang;Zhen Yue;Jingyu Liu;Jie Li;Chenglong Zheng;Yating Zhang;Yan Zhang;Jianquan Yao-.Dynamic phase assembled terahertz metalens for reversible conversion between linear polarization and arbitrary circular polarization)[J].光电进展（英文版）,2022(01):24-34

polariz,perpen,dicular

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