Dynamic phase assembled terahertz metalens for reversible conversion between linear polarization and arbitrary circular polarization
动态相位组装太赫兹元透镜用于线性偏振和任意圆偏振之间的可逆转换
直線偏光と任意の円偏光の間の可逆変換のための動的位相組み立てテラヘルツメタレン
선형 편광과 임의의 원형 편광 사이의 가역 변환을 위한 동적 위상 조립 테라헤르츠 메탈렌
Metalens de terahercios ensamblados en fase dinámica para conversión reversible entre polarización lineal y polarización circular arbitraria
Métaux térahertz assemblés en phase dynamique pour une conversion réversible entre la polarisation linéaire et la polarisation circulaire arbitraire
Терагерцовая металинза с динамической фазой для обратимого преобразования между линейной поляризацией и произвольной круговой поляризацией
Jitao Li 李继涛 ¹, Guocui Wang 汪国崔 ² ³, Zhen Yue 岳震 ¹, Jingyu Liu ³, Jie Li 李杰 ¹, Chenglong Zheng 郑程龙 ¹, Yating Zhang 张雅婷 ¹, Yan Zhang 张岩 ³, Jianquan Yao 姚建铨 ¹
¹ 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
中国 天津 天津大学光电信息技术教育部重点实验室 天津大学精密仪器与光电子工程学院
² Beijing Engineering Research Center for Mixed Reality and Advanced Display, School of Optics and Photonics, Beijing Institute of Technology, Beijing 100081, China
中国 北京 北京理工大学光电学院 北京市混合现实与新型显示工程技术研究中心
³ 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
中国 北京 首都师范大学物理系 超材料与器件北京市重点实验室 太赫兹光电子学教育部重点实验室 北京成像技术高精尖创新中心
If a metalens integrates the circular polarization (CP) conversion function, the focusing lens together with circular-polarizing 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, including 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 perpendicular LP, respectively. The metalens is expected to be used in advanced THz camera, as a great candidate for traditional CPL and focusing lens group, and also shows potential application in polarization imaging with discriminating LCP and RCP.
