• Photonics Research
  • Vol. 12, Issue 2, 356 (2024)
Huan Yuan1, Zheqiang Zhong1、2, and Bin Zhang1、2、*
Author Affiliations
  • 1College of Electronics and Information Engineering, Sichuan University, Chengdu 610064, China
  • 2Big Data Analysis and Fusion Application Technology Engineering Laboratory of Sichuan Province, Chengdu 610065, China
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    DOI: 10.1364/PRJ.509544 Cite this Article Set citation alerts
    Huan Yuan, Zheqiang Zhong, Bin Zhang. Visible-frequency nonvolatile reconfigurable Janus metasurfaces for dual-wavelength-switched and spin-asymmetric holograms[J]. Photonics Research, 2024, 12(2): 356 Copy Citation Text show less

    Abstract

    Janus metasurface holography with asymmetric transmission characteristics provides new degrees of freedom for multiplexing technologies. However, earlier metasurfaces with asymmetrical transmission faced limitations in terms of tunability and multifunctionality. In this study, we propose a metasurface color holographic encryption scheme with dynamic switching and asymmetric transmission at visible frequencies using a low-loss nonvolatile optical phase-change material, Sb2S3. Using a modified holographic optimization strategy, we achieved high-fidelity asymmetric holographic imaging of a nanostructured metasurface. By controlling the incident direction and wavelength of visible light, as well as the level of crystallization of Sb2S3, this reconfigurable metasurface enables the precise manipulation of tunable color holographic image displays. In particular, in the semi-crystalline state of Sb2S3, the encoded information can be securely encrypted using a two-channel color-holographic image, whereas only a preset camouflaged image is displayed in the crystalline or amorphous state of Sb2S3. The proposed multiencrypted Janus metasurface provides a potential approach for dynamic holographic displays with ultrahigh capacity, holographic encryption, and information storage.
    φ550/650=arg[exp(iφforward)+exp(iφbackward)],

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    φt=arg[exp(iφ550)+exp(iφ650)],

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    Hz(x,y)=exp(ikz)ikzexp[ik2z(x2+y2)]×FFT{H0(x0,y0)×exp[ik2z(x02+y02)]},

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    H0(x0,y0)=exp(ikz)ikzexp[ik2z(x02+y02)]×FFT{Hz*(x,y)×exp[ik2z(x2+y2)]},

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    εeff1εeff+2=mεC-Sb2S31εC-Sb2S3+2+(1m)εA-Sb2S31εA-Sb2S3+2,

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    Huan Yuan, Zheqiang Zhong, Bin Zhang. Visible-frequency nonvolatile reconfigurable Janus metasurfaces for dual-wavelength-switched and spin-asymmetric holograms[J]. Photonics Research, 2024, 12(2): 356
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