• Photonics Research
  • Vol. 9, Issue 6, 06001019 (2021)
Bingshuang Yao1, Xiaofei Zang1、2、*, Yang Zhu1, Dahai Yu3, Jingya Xie1、2, Lin Chen1、2, Sen Han1、4, Yiming Zhu1、2、5, and Songlin Zhuang1
Author Affiliations
  • 1Terahertz Technology Innovation Research Institute, Terahertz Spectrum and Imaging Technology Cooperative Innovation Center, Shanghai Key Laboratory of Modern Optical System, University of Shanghai for Science and Technology, Shanghai 200093, China
  • 2Shanghai Institute of Intelligent Science and Technology, Tongji University, Shanghai 200092, China
  • 3Focused Photonics (Hangzhou) Inc, Hangzhou 310052, China
  • 4Suzhou H&L Instruments LLC, Suzhou 215123, China
  • 5e-mail: ymzhu@usst.edu.cn
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    Abstract

    The control of spin electromagnetic (EM) waves is of great significance in optical communications. Although geometric metasurfaces have shown unprecedented capability to manipulate the wavefronts of spin EM waves, it is still challenging to independently manipulate each spin state and intensity distribution, which inevitably degrades metasurface-based devices for further applications. Here we propose and experimentally demonstrate an approach to designing spin-decoupled metalenses based on pure geometric phase, i.e., geometric metasurfaces with predesigned phase modulation possessing functionalities of both convex lenses and concave lenses. Under the illumination of left-/right-handed circularly polarized (LCP or RCP) terahertz (THz) waves, these metalenses can generate transversely/longitudinally distributed RCP/LCP multiple focal points. Since the helicity-dependent multiple focal points are locked to the polarization state of incident THz waves, the relative intensity between two orthogonal components can be controlled with different weights of LCP and RCP THz waves, leading to the intensity-tunable functionality. This robust approach for simultaneously manipulating orthogonal spin states and energy distributions of spin EM waves will open a new avenue for designing multifunctional devices and integrated communication systems.
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    Bingshuang Yao, Xiaofei Zang, Yang Zhu, Dahai Yu, Jingya Xie, Lin Chen, Sen Han, Yiming Zhu, Songlin Zhuang. Spin-decoupled metalens with intensity-tunable multiple focal points[J]. Photonics Research, 2021, 9(6): 06001019
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    Category: Physical Optics
    Received: Jan. 22, 2021
    Accepted: Mar. 23, 2021
    Published Online: May. 27, 2021
    The Author Email: Xiaofei Zang (xfzang@usst.edu.cn)