Dual-Polarization Analog 2D Image Processing with Nonlocal Metasurfaces

Abstract

Optical analog computing using metasurfaces has been the subject of numerous studies, aimed at implementing highly efficient and ultrafast image processing in a compact device. The proposed approaches to date have shown limitations in terms of spatial resolution, overall efficiency, polarization and azimuthal angular dependence. Here, we present the design of a polarization-insensitive metasurface with tailored nonlocality based on a Fano resonant response, enabling both odd- and even-order analog mathematical operations on an incoming image. The metasurface is formed by a single-layered triangular lattice of holes in a suspended silicon membrane, which induces a strong nonlocal response in the transverse spatial frequency spectrum. Our paper provides a path to realize highly efficient optical metasurfaces performing isotropic and polarization-insensitive edge detection on an arbitrary 2D optical image.