All-optical image recognition based on polarisation-insensitive silicon metasurfaces

Abstract

All-dielectric metasurfaces have been demonstrated recently as a promising alternative for bulky refractive optical components. In this work, we numerically investigate the correlation image processing feasibility using specially designed dielectric meta-reflect-arrays. The proposed configuration consists of silicon nanodisks immersed in a fused silica substrate realizing an amplitude and phase mask with full phase coverage of 2π and a magnitude of 0 to 1. Spectrally overlapped electric and magnetic dipole resonances allows for local and independent manipulation of the amplitude and phase of the incident electromagnetic wave. Based on these properties and the general concept of spatial Fourier transformation and filtering it is possible to realize device, which can be used for all-optical image recognition.