标题： 非局部非厄米亚表面的空域滤波 显示英文标题

标题： Spatial Filtering with Nonlocal Non-Hermitian Metasurfaces

摘要： 光学场的空间滤波在从光束整形到光学信息处理的广泛应用中具有重要作用。然而，传统的空间滤波器体积庞大且对准敏感。在这里，我们提出了非局部非厄米亚表面，它们可以在高度紧凑且对横向和纵向位移都不敏感的情况下作为极其有效的光学空间滤波器。该亚表面设计基于一种共振波导光栅，其中模式的辐射损耗被调整以在非厄米平坦带中间实现对称性保护的连续体中的束缚态。利用这种设计，我们提出了一种在法线入射周围大约1度的角度范围内工作的紧凑空间滤波装置。除了超薄且对平移错位具有鲁棒性外，所提出的亚表面易于制造，这使它们成为传统空间滤波器有吸引力的替代品，具有成为广泛使用的光学元件的潜力。 显示英文摘要

摘要： Spatial filtering of optical fields has widespread applications ranging from beam shaping to optical information processing. However, conventional spatial filters are bulky and alignment-sensitive. Here, we present nonlocal non-Hermitian metasurfaces that can act as exceptionally effective optical spatial filters while being highly compact and insensitive to both lateral and longitudinal displacements. The metasurface design is based on a resonant waveguide grating in which radiative losses of the modes are tailored to realize a symmetry-protected bound state in the continuum in the middle of a non-Hermitian flat band. Using this design, we propose a compact spatial filtering device operating over an angular range of approximately 1 degree around normal incidence. In addition to being ultrathin and robust against translational misalignment, the proposed metasurfaces are easy to manufacture, which makes them an attractive alternative to conventional spatial filters, holding a potential to become a widely used optical component.