Pixelated bifunctional metasurface-driven dynamic vectorial holographic color prints for photonic security platform

Abstract

Vectorial holography has gained a lot of attention due to the promise of versatile polarization control of structured light for enhanced optical security and multi-channel optical communication. Here, we propose a bifunctional metasurface which combines both structural color printing and vectorial holography with eight polarization channels towards advanced encryption applications. The structural colour prints are observed under white light while the polarization encoded holograms are reconstructed under laser illumination. To encode multiple holographic images for different polarization states, a pixelated metasurface is adopted. As a proof-of-concept, we devise an electrically tunable optical security platform incorporated with liquid crystals. The optical security platform is doubly encrypted: an image under white light is decrypted to provide the first key and the corresponding information is used to fully unlock the encrypted information via projected vectorial holographic images. Such an electrically tunable optical security platform may enable smart labels for security and anticounterfeiting applications.

Tunable metasurfaces towards versatile metalenses and metaholograms: a review

“…External stimuli can be classified as electrical or non-electrical stimuli. Therefore, this section presents electrically tunable [149][150][151][152][153][154][155] and non-electrically tunable 34,[156][157][158][159][160][161][162][163][164] methods to tune metaholograms.…”

“…Further, a proposed photonic security platform uses dynamic vectorial holographic images of pixelated bifunctional metasurfaces. 152 In the white light, the proposed metasurfaces show structural color prints, whereas when laser illumination passes through the metasurfaces, the encoded tunable metaholograms are reconstructed [Fig. 5 new optical encryption method exploits an improved computergenerated holography (CGH) algorithm to generate holograms that have quantitative correlation.…”

Enhancement of Luminous Intensity Emission from Incoherent LED Light Sources within the Detection Angle of 10° Using Metalenses

“…Optical metasurfaces are made up of precisely designed structures, known as meta-atoms, that can modulate the phase [ 1 , 2 ], amplitude [ 3 , 4 , 5 ], and polarization [ 6 , 7 ] of incident light. Metalenses (MLs) [ 8 , 9 , 10 , 11 , 12 , 13 , 14 ], meta-holograms [ 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 ], structural color [ 28 , 29 , 30 , 31 ], light detection [ 32 , 33 , 34 , 35 , 36 , 37 , 38 ], perfect absorber [ 39 , 40 ], and sensors [ 41 , 42 , 43 , 44 , 45 , 46 , 47 ] are typical applications of optical metasurfaces. Recently, various improvements to MLs have been repo...…”

Metasurface-enabled three-in-one nanoprints by multifunctional manipulations of light

“…By judiciously designing the geometry and orientation of each nanostructure, metasurfaces have been employed to act as optical functional elements such as metalenses ( Wang et al., 2018 ; Wang et al., 2021 ; Li et al., 2021a ; Chen et al., 2018a ; Zheng et al., 2017 ; Fu et al., 2019 ), meta-holograms ( Li et al., 2017 ; Jiang et al., 2019 ; Li et al., 2020a ; Li et al., 2020b ; Fu et al., 2020 ; Hu et al., 2019 ; Deng et al., 2020a ; Zhang et al., 2020 ; Kim et al., 2021a ; Ren et al., 2020 ), meta-gratings ( Yang et al., 2021 ; Li et al., 2018 ; Fang et al., 2020 ; Li et al., 2015a ), vortex beam generators ( Hu et al., 2021 ; Chen et al., 2018b ; Dai et al., 2020a ; Guo et al., 2016 ), and quantum information carriers ( Solntsev et al., 2021 ; Zhu et al., 2020 ; Li et al., 2020c ). Among them, metasurface-based nanoprints have attracted extensive interest due to their subwavelength resolution, durable properties, nonfading colors, and zero-pollution ( Chen et al., 2019a ; Yang et al., 2020 ; Zheng et al., 2021 ; Kim et al., 2021b ; Chen et al., 2019b ; Jung et al., 2020 ). Benefiting from the spectral tunability of metasurfaces, various approaches have been proposed to encode nanoprinting images with different colors onto a single metasurface.…”