• Photonics Research
  • Vol. 12, Issue 7, 1478 (2024)
Jiakang Zhou1, Haixiang Ma1,2, Shuoshuo Zhang1, Wu Yuan3..., Changjun Min1, Xiaocong Yuan1,2,4 and Yuquan Zhang1,*|Show fewer author(s)
Author Affiliations
  • 1Nanophotonics Research Centre, Institute of Microscale Optoelectronics & State Key Laboratory of Radio Frequency Heterogeneous Integration, Shenzhen University, Shenzhen 518060, China
  • 2Research Center for Humanoid Sensing, Research Institute of Intelligent Sensing, Zhejiang Lab, Hangzhou 311100, China
  • 3Department of Biomedical Engineering, The Chinese University of Hong Kong, Hong Kong, China
  • 4e-mail: xcyuan@szu.edu.cn
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    DOI: 10.1364/PRJ.520675 Cite this Article Set citation alerts
    Jiakang Zhou, Haixiang Ma, Shuoshuo Zhang, Wu Yuan, Changjun Min, Xiaocong Yuan, Yuquan Zhang, "Controllable split polarization singularities for ultra-precise displacement sensing," Photonics Res. 12, 1478 (2024) Copy Citation Text show less

    Abstract

    The topic of optical precise displacement measurement has garnered significant attention and generated widespread interest recently. The use of optical singularity offers a potential solution for this purpose, although effectively manipulating the singularity in an ideal manner remains challenging. In this work, we propose a theoretical approach to achieve controllable position modulation of the C-point in the focal plane, whose spatial position can be easily modulated by adjusting the relative offset factor β and the offset angle α of an azimuthal polarization beam (APB), while the interval and orientation of the C-points can be flexibly regulated. Notably, the chiral polarization state undergoes a distinct reversal along the link-line connecting the two C-points, thereby providing a promising approach for accurate displacement sensing. To evaluate its sensing characteristics, the varying pattern of the scattered field intensity is monitored when sweeping a gold helix and nanoparticle along the link-line. The results of simulation quality index Q verify that the equilibrium factor of the scattering field possesses an obvious linear relationship with the displacement, signifying a precise sub-nanometric sensitivity. This research introduces new methods for the flexible control of polarization singularities in tightly focused fields, thereby enhancing the utilization of circular polarization properties near C-points for displacement sensing. These findings not only enrich the field of nanometer measurement technology but also pave the way for new avenues of research in this domain.
    β=δR.

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    Ein=sinϕex+cosϕey,

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    ϕ=arctan(yx),

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    ϕ=arctan(y+βRsinαx+βRcosα),

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    Ein=sinϕex+cosϕey.

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    E(r,φ,z=0)=ikf2π0θ02πcosθ[(sinϕ(cos2ϕcosθ+sin2ϕ)+cosϕcosϕsinϕ(cosθ1))ex(sinϕsinϕcosϕ(cosθ1)+cosϕ(cos2ϕcosθ+sin2ϕ))ey(cosϕsinϕcosϕsinϕ)sinθez]×exp(ikrsinθcos(φϕ))sinθdθdϕ,

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    S1+iS2=Aijexp(iϕ12),

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    σ12=12πcdϕ12,

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    S=Im[E*×E]E*·E,

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    Jiakang Zhou, Haixiang Ma, Shuoshuo Zhang, Wu Yuan, Changjun Min, Xiaocong Yuan, Yuquan Zhang, "Controllable split polarization singularities for ultra-precise displacement sensing," Photonics Res. 12, 1478 (2024)
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