Abstract Spatial differentiator is the key element for edge detection, which is indispensable in image processing, computer vision involving image recognition, image restoration, image compression, and so on. Spatial differentiators based on metasurfaces are simpler and more compact compared with traditional bulky optical analog differentiators. However, most of them still rely on complex optical systems, leading to the degraded compactness and efficiency of the edge detection systems. To further reduce the complexity of the edge detection system, a monolithic metasurface spatial differentiator is demonstrated based on asymmetric photonic spin-orbit interactions. Edge detection can be accomplished via such a monolithic metasurface using the polarization degree. Experimental results show that the designed monolithic spatial differentiator works in a broadband range. Moreover, 2D edge detection is experimentally demonstrated by the proposed monolithic metasurface. The proposed design can be applied at visible and near-infrared wavelengths by proper dielectric materials and designs. We envision this approach may find potential applications in optical analog computing on compact optical platforms.

中文翻译：

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由不对称光子自旋轨道相互作用实现的单片超表面空间微分器

摘要 空间微分器是边缘检测的关键要素，在图像处理、计算机视觉涉及图像识别、图像恢复、图像压缩等领域中必不可少。与传统庞大的光学模拟微分器相比，基于超表面的空间微分器更简单、更紧凑。然而，它们中的大多数仍然依赖于复杂的光学系统，导致边缘检测系统的紧凑性和效率下降。为了进一步降低边缘检测系统的复杂性，基于不对称光子自旋轨道相互作用展示了单片超表面空间微分器。边缘检测可以通过使用偏振度的单片超表面来完成。实验结果表明，设计的单片空间微分器在宽带范围内工作。此外，所提出的单片超表面通过实验证明了二维边缘检测。通过适当的介电材料和设计，所提出的设计可以应用于可见光和近红外波长。我们设想这种方法可能会在紧凑型光学平台上的光学模拟计算中找到潜在的应用。