Integrated photonic circuits are created as a stable and small form factor analogue of fiber-based optical systems, from wavelength-division multiplication transceivers to more recent mode-division multiplexing components. Silicon nanowire waveguides guide the light in a way that single and few mode fibers define the direction of signal flow. Beyond communication tasks, on-chip cascaded interferometers and photonic meshes are also sought for optical computing and advanced signal processing technology. Here we review an alternative way of defining the light flow in the integrated photonic platform, using arrays of subwavelength meta-atoms or metalines for guiding the diffraction and interference of light. The integrated metasurface system mimics free-space optics, where on-chip analogues of basic optical components are developed with foundry compatible geometry, such as low-loss lens, spatial-light modulator, and other wavefront shapers. We discuss the role of metasurface in integrated photonic signal processing systems, introduce the design principles of such metasurface systems for low loss compact mode conversion, mathematical operation, diffractive optical systems for hyperspectral imaging, and tuning schemes of metasurface systems. Then we perceive reconfigurability schemes for metasurface framework, toward optical neural networks and analog photonic accelerators.

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集成光子平台上的超表面：从模式转换器到机器学习

集成光子电路被创建为基于光纤的光学系统的稳定和小型模拟，从波分倍增收发器到更新的模分复用组件。硅纳米线波导以单模光纤和少模光纤定义信号流方向的方式引导光。除了通信任务，片上级联干涉仪和光子网格也被用于光学计算和先进的信号处理技术。在这里，我们回顾了在集成光子平台中定义光流的另一种方法，使用亚波长元原子或金属线阵列来引导光的衍射和干涉。集成的超表面系统模仿自由空间光学，其中基本光学元件的片上类似物是通过与代工厂兼容的几何结构开发的，例如低损耗透镜、空间光调制器和其他波前整形器。我们讨论了超表面在集成光子信号处理系统中的作用，介绍了这种超表面系统用于低损耗紧凑模式转换、数学运算、用于高光谱成像的衍射光学系统以及超表面系统的调谐方案的设计原理。然后我们感知超表面框架的可重构方案，面向光学神经网络和模拟光子加速器。介绍了用于低损耗紧凑模式转换、数学运算、用于高光谱成像的衍射光学系统以及超表面系统的调谐方案的此类超表面系统的设计原理。然后我们感知超表面框架的可重构方案，面向光学神经网络和模拟光子加速器。介绍了用于低损耗紧凑模式转换、数学运算、用于高光谱成像的衍射光学系统以及超表面系统的调谐方案的此类超表面系统的设计原理。然后我们感知超表面框架的可重构方案，面向光学神经网络和模拟光子加速器。