High-Index Dielectric Metasurfaces Performing Mathematical Operations
High-Index Dielectric Metasurfaces Performing Mathematical Operations
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DOI：
10.1021/acs.nanolett.9b02477
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发表时间：
2019-12-01
期刊：
影响因子：
10.8
通讯作者：
Polman, Albert
中科院分区：
文献类型：
--
作者：
Cordaro, Andrea;Kwon, Hoyeong;Polman, Albert
图像处理和边缘检测是几项新兴技术的核心，如增强现实、自动驾驶，以及更普遍的物体识别。图像处理通常使用集成电路和算法以数字方式执行，这意味着基本的尺寸和速度限制，以及显著的功率需求。另一方面，它也可以使用傅里叶光学以低功率模拟方式执行，然而，需要笨重的光学部件。在这里，我们介绍了介电元表面，它使用亚波长几何结构在模拟域执行光学图像边缘检测，该几何结构可以很容易地与探测器集成。该亚表面由设计用于执行一阶或二阶空间微分的适当设计的纳米棒阵列组成。我们在一幅输入图像上实验演示了二阶导数运算，展示了在数值孔径为0.35的情况下使用硅亚表面几何结构进行全光学边缘检测的潜力。
Image processing and edge detection are at the core of several newly emerging technologies, such as augmented reality, autonomous driving, and more generally object recognition. Image processing is typically performed digitally using integrated electronic circuits and algorithms, implying fundamental size and speed limitations, as well as significant power needs. On the other hand, it can also be performed in a low-power analog fashion using Fourier optics, requiring, however, bulky optical components. Here, we introduce dielectric metasurfaces that perform optical image edge detection in the analog domain using a subwavelength geometry that can be readily integrated with detectors. The metasurface is composed of a suitably engineered array of nanobeams designed to perform either first- or second-order spatial differentiation. We experimentally demonstrate the second-derivative operation on an input image, showing the potential of all-optical edge detection using a silicon metasurface geometry working at a numerical aperture as large as 0.35.