Chinese Optics Letters, Volume. 23, Issue 6, 062601(2025)
Generation and manipulation of multiple multidimensional perfect Poincaré beams enabled by a single-layer all-dielectric geometric metasurface
Fig. 1. Schematic diagram and working principle for generating multiple PPBs with polarization variation along arbitrary spatial trajectories through a single geometric metasurface. (a) Top, schematic illustrations of a metasurface device capable of producing multiple PPBs with tailored polarization states along customized 3D spatial paths when illuminated by LP light. Bottom, phase profiles embedded on the metasurface achieved by combining the phases of a spiral phase plate, an axicon, and a Fourier lens. (b) Left, operation principle for the generation of PPB with the proposed geometric metasurface. Right, perspective and top views showcasing the anisotropic elementary unit comprising a Ge2Sb2Se4Te1 (GSST) nanopillar array arranged on a CaF2 square substrate. (c) Simulated transmission coefficients (Txx, Tyy) and phase shifts (ϕxx, ϕyy) of the optimized meta-atom under x- and y-polarized illuminations across various incident wavelengths.
Fig. 2. Generation of four distinct mode PPBs (mode 1, mode 2, mode 3, and mode 4) using four metasurface samples (MF1, MF2, MF3, and MF4) under x-linearly polarized illumination. (a) Simulated electric field intensities in the x–z plane for the four-mode PPBs at the operational wavelength of λo = 4.4 µm. (b) Simulated horizontal cross-sections of the annular intensity at the designed focal position z = 200 µm for the four distinct mode PPBs. (c) Theoretical (black bars) and simulated (red bars) radii of the annular intensity for the four distinct mode PPBs at the designed focal position z = 200 µm. (d) Simulated radii of the annular intensity for the four-mode PPBs in two additional observation planes at z = 140 and z = 260 µm. (e) The thickness of the annular intensity for the four-mode PPBs at the designated focal position z = 200 µm. (f) Four selected points on HyOPS representing distinct polarization states of the four-mode PPBs sequentially generated by four metasurfaces. (g) Simulated component intensity patterns at focal planes captured through polarizers oriented differently for the four-mode PPBs. (h) Computed Stokes parameters (S0, S1, S2, and S3) and polarization orientations (Ω) at focal planes for the four-mode PPBs. The white arrows within S0 patterns indicate the polarization states of the four-mode PPBs.
Fig. 3. Generation of eightfold PPBs with varying polarizations along the designated cylindrical helical trajectory using metasurface sample MF5 under x-linearly polarized illumination. (a) Simulated cross-sectional intensity profiles of the Ex-components in the eight prescribed focal planes following the designated cylindrical helical path. (b) Theoretical (black bars) and simulated (red bars) radii of the annular intensity for the eightfold PPBs in their individual focal planes. (c) The precise spatial positions of the eightfold PPBs along the designated cylindrical helical path in 3D space. (d) The longitudinal polarization evolution of the generated eightfold PPBs on the HyOPS. (e) Rows 1 to 6: simulated component intensity patterns at focal planes captured through polarizers oriented differently for the eightfold PPBs generated by a single metasurface. Rows 7 to 11: calculated Stokes parameters (S0, S1, S2, and S3) and polarization orientations (Ω) at focal planes for the eightfold PPBs. The white arrows within the S0 patterns indicate the polarization states of the eightfold PPBs.
Fig. 4. Schematic of the metasurface sample MF6-based OAM and polarization state multi-dimensional encoding for optical information encryption. (a1) Schematic representation of encoding 32-fold PPBs within two target focal planes using MF6 under x-linearly polarized illumination. (a2) Designed 16 polarization orders ranging from 1 to 8.5 with an increment of 0.5. (a3) Designed 16 polarization orientations ranging from 0 to π with an increment of π/15. (b) and (c) Column 1: simulated cross-sectional intensity profiles of transmitted orthogonally polarized PVB arrays on the (b) first and (c) second target focal planes produced by MF6 under LCP incidence. Columns 2 and 3: calculated x- and y-component intensities of PPB arrays on the (b) first and (c) second target focal planes generated by MF6 under x-linearly polarized incidence. Column 4: simulated electric vector distributions (top panel) and polarization orientations (bottom panel) of PPBs carrying polarization order p = 1. (d) Designed 32 double-digit hexadecimal numbers from 00 to FF represented by 32 different kinds of PPBs. Here, 2 polarization orientations Ω, 0 and π, denote the first hexadecimal digits 0 and F, 16 polarization orders p spanning from 1 to 8.5 with increments of 0.5, correspond to the second hexadecimal digit from 0 to F. (e) Encoding method and code chart. This encoding scheme can effectively map the 26 English letters and 6 function keys on a standard keyboard with our designed 32 double-digit hexadecimal numbers from 00 to FF. (f) The revealed 115 various double-digit hexadecimal number sequences representing the encrypted information decoded based on ASCII. (g) and (h) Plaintext message decrypted by the received 115 double-digit hexadecimal numbers.
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Ximin Tian, Shenglan Zhang, Yaning Xu, Junwei Xu, Yafeng Huang, Liang Li, Jielong Liu, Kun Xu, Xiaolong Ma, Linjie Fu, Zhi-Yuan Li, "Generation and manipulation of multiple multidimensional perfect Poincaré beams enabled by a single-layer all-dielectric geometric metasurface," Chin. Opt. Lett. 23, 062601 (2025)
Category: Physical Optics
Received: Aug. 29, 2024
Accepted: Jan. 7, 2025
Posted: Jan. 7, 2025
Published Online: May. 23, 2025
The Author Email: Junwei Xu (xujunwei001@zua.edu.cn), Zhi-Yuan Li (phzyli@scut.edu.cn)