中国物理B ›› 2022, Vol. 31 ›› Issue (11): 118103-118103.doi: 10.1088/1674-1056/ac6494

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Enhanced and tunable circular dichroism in the visible waveband by coupling of the waveguide mode and local surface plasmon resonances in double-layer asymmetric metal grating

Liu-Li Wang(王刘丽)1, Yang Gu(顾阳)1, Yi-Jing Chen(陈怡静)1, Ya-Xian Ni(倪亚贤)2,†, and Wen Dong(董雯)1,‡   

  1. 1 School of Physical Science and Technology, Soochow University, Suzhou 215006, China;
    2 Soochow College, Soochow University, Suzhou 215006, China
  • 收稿日期:2021-11-23 修回日期:2022-03-27 接受日期:2022-04-06 出版日期:2022-10-17 发布日期:2022-10-17
  • 通讯作者: Ya-Xian Ni, Wen Dong E-mail:niyaxian@suda.edu.cn;dongwen@suda.edu.cn
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant No. 11474215).

Enhanced and tunable circular dichroism in the visible waveband by coupling of the waveguide mode and local surface plasmon resonances in double-layer asymmetric metal grating

Liu-Li Wang(王刘丽)1, Yang Gu(顾阳)1, Yi-Jing Chen(陈怡静)1, Ya-Xian Ni(倪亚贤)2,†, and Wen Dong(董雯)1,‡   

  1. 1 School of Physical Science and Technology, Soochow University, Suzhou 215006, China;
    2 Soochow College, Soochow University, Suzhou 215006, China
  • Received:2021-11-23 Revised:2022-03-27 Accepted:2022-04-06 Online:2022-10-17 Published:2022-10-17
  • Contact: Ya-Xian Ni, Wen Dong E-mail:niyaxian@suda.edu.cn;dongwen@suda.edu.cn
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant No. 11474215).

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摘要： Circular dichroism (CD) has shown very interesting possibilities as a means to characterize the chiral signal of a chiral structure. Here, we theoretically demonstrated enhanced and tunable CD in the visible light regime using a composite structure consisting of a double-layer metal grating gaped by a dielectric waveguide layer. Based on the coupling of the waveguide modes and the localized plasmonic resonances, the CD could reach a maximum value as high as 0.52 at 635 nm, which is four times higher than the CD value obtained in a conventional double-layer grating without the waveguide coupling effect. Furthermore, the spectral positions of the enhanced CD bands could be easily tuned by controlling the structural parameters. The proposed hybrid double-grating and waveguide structures could have potential applications in chiral selective imaging, sensing and spectroscopy, especially where the transmission measurement is required.

关键词: circular dichroism, chiral metamaterial, waveguide, surface plasmon

Abstract: Circular dichroism (CD) has shown very interesting possibilities as a means to characterize the chiral signal of a chiral structure. Here, we theoretically demonstrated enhanced and tunable CD in the visible light regime using a composite structure consisting of a double-layer metal grating gaped by a dielectric waveguide layer. Based on the coupling of the waveguide modes and the localized plasmonic resonances, the CD could reach a maximum value as high as 0.52 at 635 nm, which is four times higher than the CD value obtained in a conventional double-layer grating without the waveguide coupling effect. Furthermore, the spectral positions of the enhanced CD bands could be easily tuned by controlling the structural parameters. The proposed hybrid double-grating and waveguide structures could have potential applications in chiral selective imaging, sensing and spectroscopy, especially where the transmission measurement is required.

Key words: circular dichroism, chiral metamaterial, waveguide, surface plasmon

中图分类号:  (Metamaterials for chiral, bianisotropic and other complex media)

  • 81.05.Xj
73.20.Mf (Collective excitations (including excitons, polarons, plasmons and other charge-density excitations)) 42.79.Gn (Optical waveguides and couplers) 42.79.Dj (Gratings)