• Photonics Research
  • Vol. 11, Issue 11, 1880 (2023)
Xinhao Jiang1, Yunyun Ji1、2、*, Fei Fan1、3、4, Songlin Jiang1, Zhiyu Tan1, Huijun Zhao1, Jierong Cheng1, and Shengjiang Chang1、3、5
Author Affiliations
  • 1Institute of Modern Optics, Nankai University, Tianjin 300350, China
  • 2Tianjin Key Laboratory of Micro-scale Optical Information Science and Technology, Tianjin 300350, China
  • 3Tianjin Key Laboratory of Optoelectronic Sensor and Sensing Network Technology, Tianjin 300350, China
  • 4e-mail: fanfei@nankai.edu.cn
  • 5e-mail: sjchang@nankai.edu.cn
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    DOI: 10.1364/PRJ.501047 Cite this Article Set citation alerts
    Xinhao Jiang, Yunyun Ji, Fei Fan, Songlin Jiang, Zhiyu Tan, Huijun Zhao, Jierong Cheng, Shengjiang Chang. Arbitrary terahertz chirality construction and flexible manipulation enabled by anisotropic liquid crystal coupled chiral metasurfaces[J]. Photonics Research, 2023, 11(11): 1880 Copy Citation Text show less

    Abstract

    Chiral metasurfaces integrated with active materials can dynamically control the chirality of electromagnetic waves, making them highly significant in physics, chemistry, and biology. Herein, we theoretically proposed a general and feasible design scheme to develop a chiral metadevice based on a bilayer anisotropic metasurface and a monolayer liquid crystal (LC), which can construct and flexibly manipulate arbitrary terahertz (THz) chirality. When the twist angle between the anisotropic axes of two metasurfaces θ is not 0°, the spatial mirror symmetry of the chiral metadevice is broken, resulting in a strong THz chiral response. In addition, the introduction of anisotropic LCs not only enhances the chiral response of the metadevice but also induces the flipping modulation and frequency tunability of the chirality. More importantly, by optimizing the θ, we can flexibly design the arbitrary chiral response and the operating frequency of chirality, thereby promoting the emergence of various chiral manipulation devices. The experimental results show that the maximum circular dichroism can reach -33 dB at 0.94 THz and flip to 28 dB at 0.69 THz by rotating the LC optical axis from the x to y axis, with the maximum operating frequency tunable range of 120 GHz. We expect this design strategy can create new possibilities for the advancement of active THz chiral devices and their applications, including chiral spectroscopy, molecular recognition, biosensing, and fingerprint detection.
    TMS(θ)=[Axcos2θ2+Ayeiφsin2θ2(AyeiφAx)sinθ2cosθ2(AyeiφAx)sinθ2cosθ2Axsin2θ2+Ayeiφcos2θ2]=[S1DDS2],

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    TLC(α)=[Axeiδ/2cos2α+Ayeiδ/2sin2α(Axeiδ/2Ayeiδ/2)sin2α2(Axeiδ/2Ayeiδ/2)sin2α2Axeiδ/2sin2α+Ayeiδ/2cos2α]=[S1DDS2],

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    Ttotal_LP=[S1DDS2][S1DDS2][S1DDS2].

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    [ExEy]=12[11ii][EREL]=C[EREL].

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    Ttotal_CP=C1Ttotal_LPC=14[S1S12+S2S22D2(S1+S2)+i2D(S1S1S2S2)S1S12S2S22+D2(S1S2)+i2D(S1S2D2)S1S12S2S22+D2(S1S2)+i2D(D2S1S2)S1S12+S2S22D2(S1+S2)+i2D(S2S2S1S1)]=[tRRtRLtLRtLL],

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    Co-CD=TRRTLL,

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    T=(tRRtRLtLRtLL)=12(t++45°+t45°+i(t+45°t+45°)t++45°t45°i(t+45°+t+45°)t++45°t45°+i(t+45°+t+45°)t++45°+t45°i(t+45°t+45°)).(D1)

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    (ExA+45°)2+(EyA45°)22ExEyA+45°A45°cosΔφ=sin2Δφ,(D2)

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    PEA=12arcsin(sin2εsinΔφ),PRA=12arctan(tan2εcosΔφ),(D3)

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    Xinhao Jiang, Yunyun Ji, Fei Fan, Songlin Jiang, Zhiyu Tan, Huijun Zhao, Jierong Cheng, Shengjiang Chang. Arbitrary terahertz chirality construction and flexible manipulation enabled by anisotropic liquid crystal coupled chiral metasurfaces[J]. Photonics Research, 2023, 11(11): 1880
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