DOI: 10.3390/photonics13080740 ISSN: 2304-6732

All-Dielectric Stochastically Encoded Metasurface for Multifunctional Imaging Across Six-Polarization Channels

Linkun Zhang, Shangshang Cui, Mengfei Li, Xin Cai, Wenjing Fang, Xinye Fan, Xiaowei Yang, Xueli Geng

We proposed an all-dielectric stochastically encoded metasurface operating in the 1310 nm near-infrared band, which enables multifunctional optical field manipulation across six independent polarization channels. Utilizing a shared-aperture stochastic matrix-encoding strategy combined with cooperative propagation and geometric-phase decoupling modulation, we investigated stochastically encoded phase distributions, vortex beam profiles, near-diffraction-limited focusing profiles, and the characterization of complex-amplitude multifocal focusing under six independent polarizations. Under left- and right-circularly polarized (LCP/RCP) illumination, vortex beams with topological charges of 1 and 2 have demonstrated substantial enhancement in spatial edge contrast, achieving high edge contrasts of 20 dB and 7.45 dB, respectively, enabling high-fidelity extraction of fine structural boundaries for edge-enhanced imaging. In contrast, near-diffraction-limited focusing under x- and y-polarized illumination has been achieved with numerical apertures (NA) of 0.66 and 0.59, facilitating the realization of bright-field imaging. Significantly, parallel imaging based on complex-amplitude multifocal spot arrays exhibits markedly improved channel isolation, achieving high power ratios of 88.8% and 94.5% under 45° and 135° linearly polarized excitation, respectively. The compact shared-aperture architecture integrates all polarization-controlled functionalities without mechanical tuning, enabling polarization-switchable bright-field imaging, edge detection, and parallel optical manipulation in the near-infrared band.

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