Reconfigurable Metasurface for Image Processing

TLDR

Optical Fourier transform processing offers fast, high‑throughput computation, and recent flat‑optics implementations enable compact devices, but existing designs are static and cannot change the operator. This work demonstrates a reconfigurable metasurface that can be dynamically tuned to perform bright‑field imaging, low‑pass and high‑pass filtering, and second‑order differentiation. The metasurface is directly integrated with conventional coherent imaging systems, achieving a numerical aperture of 0.25 and a 60‑nm bandwidth while allowing dynamic tuning. Dynamic wave‑vector control in a compact metasurface opens possibilities for microscopy, machine vision, and sensing applications.

Abstract

Optical Fourier transform-based processing is an attractive technique due to the fast processing times and large-data rates. Furthermore, it has recently been demonstrated that certain Fourier-based processors can be realized in compact form factors using flat optics. The flat optics, however, have been demonstrated as static filters where the operator is fixed, limiting the applicability of the approach. Here, we demonstrate a reconfigurable metasurface that can be dynamically tuned to provide a range of processing modalities including bright-field imaging, low-pass and high-pass filtering, and second-order differentiation. The dynamically tunable metasurface can be directly combined with standard coherent imaging systems and operates with a numerical aperture up to 0.25 and over a 60 nm bandwidth. The ability to dynamically control light in the wave vector domain, while doing so in a compact form factor, may open new doors to applications in microscopy, machine vision, and sensing.