Racemic dielectric metasurfaces for arbitrary terahertz polarization rotation and wavefront manipulation
用于任意太赫兹偏振旋转和波前操纵的外消旋介电超表面
任意のテラヘルツ偏光回転と波面操作のためのラセミ誘電体超表面
임의의 테라헤르츠 편광 회전과 파전 조종에 사용되는 외소선 개전 초표면
Supersuperficies dieléctrica de eliminación externa para rotación polarizada arbitraria de terahertz y manipulación del Frente de onda
Supersurface diélectrique racémique pour rotation de polarisation Térahertz arbitraire et manipulation de front d'onde
внешняя спин - диэлектрическая суперповерхность для вращения с произвольной терагерцовой поляризацией и управления волновым фронтом
Jie Li 李杰 ¹ ², Xueguang Lu 路学光 ³, Hui Li 李辉 ², Chunyu Song 宋春宇 ², Qi Tan 谭琪 ², Yu He 何宇 ¹, Jingyu Liu 刘婧宇 ⁶, Li Luo 罗莉 ¹, Tingting Tang 唐婷婷 ¹, Tingting Liu 刘婷婷 ⁴, Hang Xu 徐航 ², Shuyuan Xiao 肖书源 ⁴, Wanxia Huang 黄婉霞 ³, Yun Shen 沈云 ⁵, Yan Zhang 张岩 ⁶, Yating Zhang 张雅婷 ², Jianquan Yao 姚建铨 ²
¹ College of Optoelectronic Engineering, Chengdu University of Information Technology, Chengdu 610225, China
中国 成都 成都信息工程大学 光电工程学院
² School of Precision Instruments and Opto-Electronics Engineering, Tianjin University, Tianjin, 300072, China
中国 天津 天津大学 精密仪器与光电子工程学院
³ College of Materials Science and Engineering, Sichuan University, Chengdu 610065, China
中国 成都 四川大学 材料科学与工程学院
⁴ School of Information Engineering, Nanchang University, Nanchang 330031, China
中国 南昌 南昌大学 信息工程学院
⁵ Department of Physics, School of Physics and Materials Science, Nanchang University, Nanchang 330031, China
中国 南昌 南昌大学 物理与材料学院 物理系
⁶ Key Laboratory of Terahertz Optoelectronics, Ministry of Education, Department of Physics, Capital Normal University, Beijing 100048, China
中国 北京 首都师范大学 太赫兹光电子学教育部重点实验室
Dielectric chiral metasurface is a new type of planar and efficient chiral optical device that shows strong circular dichroism or optical activity, which has important application potential in optical sensing and display. However, the two types of chiral optical responses in conventional chiral metasurfaces are often interdependent, as their modulation of the amplitudes and phases of orthogonal circularly polarized components is correlated, which limits the further progress of chiral meta-devices.
Here we propose a new scheme for independently designing the circular dichroism and optical activity of chiral metasurfaces to further control the polarization and wavefront of transmitted waves. Inspired by mixtures of chiral molecular isomers, we use the dielectric isomer resonators to form “super-units” instead of single meta-atoms for chiral responses in terahertz band, which is called racemic metasurface.
By introducing two levels of Pancharatnam-Berry phases between meta-atoms and “super-units”, the polarization rotation angle and wavefront of the beam can be designed without the far-field circular dichroism. We demonstrate the strong control ability on terahertz waves of this scheme through simulation and experiments. In addition, this new type of device with near-field chirality but no far-field circular dichroism may also have important value in optical sensing and other technologies.
