Liu Tingting, Qiu Jumin, Xu Lei, Qin Meibao, Wan Lipeng, Yu Tianbao, Liu Qiegen, Huang Lujun, Xiao Shuyuan
School of Information Engineering, Nanchang University, Nanchang 330031, China.
Institute for Advanced Study, Nanchang University, Nanchang 330031, China.
Nano Lett. 2024 Nov 13;24(45):14466-14474. doi: 10.1021/acs.nanolett.4c04543. Epub 2024 Oct 30.
Optical metasurfaces have revolutionized analog computing and image processing at subwavelength scales with faster speed and lower power consumption. They typically involve spatial differentiation with an engineered angular dispersion. Quasi-bound states in the continuum (quasi-BICs) have emerged as powerful tools for customizing optical resonances. While quasi-BICs have been widely used with high -factors and enhanced field confinement, their potential in image processing remains unexplored. Here, we demonstrate edge detection imaging by leveraging quasi-BIC in an all-dielectric metasurface. This metasurface, composed of four nanodisks per unit cell, supports a polarization-independent quasi-BIC through structural perturbations, allowing simultaneously engineering -factor and angular dispersion. It can perform isotropic two-dimensional spatial differentiation, which is crucial for edge detection. We fabricate the metasurfaces and validate their efficient, high-quality edge detection under different polarizations. Our findings illuminate the mechanisms of edge detection with quasi-BIC metasurfaces, opening new avenues for ultracompact, low-power optical computing devices.
光学超表面以更快的速度和更低的功耗，在亚波长尺度上彻底改变了模拟计算和图像处理。它们通常涉及具有工程化角色散的空间微分。连续统中的准束缚态（quasi-BICs）已成为定制光学共振的强大工具。虽然准束缚态已被广泛用于高因子和增强场限制，但它们在图像处理中的潜力仍未得到探索。在这里，我们展示了通过利用全介质超表面中的准束缚态进行边缘检测成像。这种超表面由每个单元四个纳米盘组成，通过结构扰动支持与偏振无关的准束缚态，从而能够同时控制因子和角色散。它可以执行各向同性的二维空间微分，这对于边缘检测至关重要。我们制造了这些超表面，并验证了它们在不同偏振下高效、高质量的边缘检测能力。我们的发现阐明了准束缚态超表面的边缘检测机制，为超紧凑、低功耗光学计算设备开辟了新途径。
