A single metagrating metastructure for wave-based parallel analog computing

TL;DR

This paper introduces a novel multi-functional metagrating that can perform parallel analog computations by modulating both spatial and angular properties of wave signals, enabling advanced optical signal processing.

Contribution

It presents a new metagrating design capable of simultaneous spatial and angular modulation, allowing multiple analog computing functions on a single integrated surface.

Findings

Successfully demonstrated parallel spatial differentiation tasks

Validated phase and amplitude extraction of diffractive modes

Achieved multi-channel optical processing with a single metastructure

Abstract

Wave-based signal processing has witnessed a significant expansion of interest in a variety of science and engineering disciplines, as it provides new opportunities for achieving high-speed and low-power operations. Although flat optics desires integrable components to perform multiple missions, yet, the current wave-based analog computers can engineer only the spatial content of the input signal where the processed signal obeys the traditional version of Snell's law. In this paper, we propose a multi-functional metagrating to modulate both spatial and angular properties of the input signal whereby both symmetric and asymmetric optical transfer functions are realized using high-order space harmonics. The performance of the designed compound metallic grating is validated through several investigations where closed-form expressions are suggested to extract the phase and amplitude information of the diffractive modes. Several illustrative examples are demonstrated to show that the proposed metagrating allows for simultaneous parallel analog computing tasks such as first- and second-order spatial differentiation through a single multi-channel structured surface. It is anticipated that the designed platform brings a new twist to the field of optical signal processing and opens up large perspectives for simple integrated image processing systems.