中国物理B ›› 2025, Vol. 34 ›› Issue (4): 44205-044205.doi: 10.1088/1674-1056/adad55

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Broadband polarization-independent terahertz multifunctional liquid crystal coding metasurface based on topological optimization

Yu Chen(陈羽)1, Wu-Hao Cao(曹吴昊)1, Jia-Qi Li(李嘉琦)1, Ming-Zhe Zhang(张明哲)1, Xin-Yi Du(杜欣怡)1, Ding-Shan Gao(郜定山)2, and Pei-Li Li(李培丽)1,†   

  1. 1 Nanjing University of Posts and Telecommunications, Nanjing 210003, China;
    2 Wuhan National Laboratory for Optoelectronics, College of Optoelectronic Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
  • 收稿日期:2024-12-19 修回日期:2025-01-13 接受日期:2025-01-23 出版日期:2025-04-15 发布日期:2025-04-15
  • 通讯作者: Pei-Li Li E-mail:lipl@njupt.edu.cn
  • 基金资助:
    Project supported by the Open Fund of Wuhan National Research Center for Optoelectronics (Grant No. 2022WNLOKF012) and the National College Students Innovation and Entrepreneurship Training Program (Grant No. 2023102930147).

Broadband polarization-independent terahertz multifunctional liquid crystal coding metasurface based on topological optimization

Yu Chen(陈羽)1, Wu-Hao Cao(曹吴昊)1, Jia-Qi Li(李嘉琦)1, Ming-Zhe Zhang(张明哲)1, Xin-Yi Du(杜欣怡)1, Ding-Shan Gao(郜定山)2, and Pei-Li Li(李培丽)1,†   

  1. 1 Nanjing University of Posts and Telecommunications, Nanjing 210003, China;
    2 Wuhan National Laboratory for Optoelectronics, College of Optoelectronic Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
  • Received:2024-12-19 Revised:2025-01-13 Accepted:2025-01-23 Online:2025-04-15 Published:2025-04-15
  • Contact: Pei-Li Li E-mail:lipl@njupt.edu.cn
  • Supported by:
    Project supported by the Open Fund of Wuhan National Research Center for Optoelectronics (Grant No. 2022WNLOKF012) and the National College Students Innovation and Entrepreneurship Training Program (Grant No. 2023102930147).

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摘要： A broadband polarization-independent terahertz multifunctional coding metasurface based on topological optimization using liquid crystal (LC) is proposed. The metasurface can achieve reconfigurability for beam steering and vortex beam generation within a frequency range of 0.68 THz-0.72 THz. Firstly, the metasurface unit is topologically optimized using the non-dominant sequencing genetic algorithms (NSGA-II) multi-objective optimization algorithm. By applying the LC's electrically tunable refractive index properties, the metasurface unit enables polarization-independent 2-bit coding within a frequency range of 0.68 THz-0.72 THz. Then, based on the designed metasurface unit, the array arrangement of the metasurface is reverse-designed to achieve beam steering and vortex beam generation. The results show that, for beam steering, not only can polarization-independent steering of both single- and multi-beam be achieved within the 35$^\circ$ elevation angle range, but also independent control of the target angle of each beam in the multi-beam steering. For vortex beam generation, the metasurfaces can achieve the generation of single- and multi-vortex beams with topological charges $l=\pm 1$, $\pm 2$ within the 35$^\circ$ elevation angle range, and the generation angles of each vortex beam in the multi-vortex beam can be independently controlled. This provides flexibility and diversity in the generation of vortex beams. Therefore, the proposed terahertz LC metasurface can realize flexible control of reconfigurable functions and has certain application prospects in terahertz communication, phased array radar, and vortex radar.

关键词: coding metasurfaces, polarization-independent, terahertz, topology optimization

Abstract: A broadband polarization-independent terahertz multifunctional coding metasurface based on topological optimization using liquid crystal (LC) is proposed. The metasurface can achieve reconfigurability for beam steering and vortex beam generation within a frequency range of 0.68 THz-0.72 THz. Firstly, the metasurface unit is topologically optimized using the non-dominant sequencing genetic algorithms (NSGA-II) multi-objective optimization algorithm. By applying the LC's electrically tunable refractive index properties, the metasurface unit enables polarization-independent 2-bit coding within a frequency range of 0.68 THz-0.72 THz. Then, based on the designed metasurface unit, the array arrangement of the metasurface is reverse-designed to achieve beam steering and vortex beam generation. The results show that, for beam steering, not only can polarization-independent steering of both single- and multi-beam be achieved within the 35$^\circ$ elevation angle range, but also independent control of the target angle of each beam in the multi-beam steering. For vortex beam generation, the metasurfaces can achieve the generation of single- and multi-vortex beams with topological charges $l=\pm 1$, $\pm 2$ within the 35$^\circ$ elevation angle range, and the generation angles of each vortex beam in the multi-vortex beam can be independently controlled. This provides flexibility and diversity in the generation of vortex beams. Therefore, the proposed terahertz LC metasurface can realize flexible control of reconfigurable functions and has certain application prospects in terahertz communication, phased array radar, and vortex radar.

Key words: coding metasurfaces, polarization-independent, terahertz, topology optimization

中图分类号:  (General topology)

  • 02.40.Pc
42.70.Df (Liquid crystals) 61.30.-v (Liquid crystals) 07.05.Tp (Computer modeling and simulation) 42.25.Bs (Wave propagation, transmission and absorption)