# Double-phase metasurface operators for all-optical image processing

## TL;DR

This paper introduces a compact optical computing platform using metasurfaces for fast, energy-efficient image processing and high-resolution holography.

## Contribution

A novel metasurface-based platform using double-phase encoding and polarization multiplexing for all-optical analog computing.

## Key findings

- The platform enables arbitrary image transformations in a single passive nanophotonic device.
- Key operations like differentiation and cross-correlation are demonstrated experimentally.
- High-fidelity complex holography with subwavelength-scale control is achieved.

## Abstract

All-optical image processing offers a high-speed, energy-efficient alternative to conventional electronic systems by leveraging the wave nature of light for parallel computation. However, traditional optical processors rely on bulky components, limiting scalability and integration. Here, we demonstrate a compact metasurface-based platform for analog optical computing. By employing double-phase encoding and polarization multiplexing, our approach enables arbitrary image transformations within a single passive nanophotonic device, eliminating the need for complex optical setups or digital post-processing. We experimentally showcase key computational operations, including first-order differentiation, cross-correlation, vertex detection, and Laplacian differentiation. Additionally, we extend this framework to high-resolution complex holography, achieving subwavelength-scale volumetric wavefront control for depth-resolved reconstructions with high fidelity. Our results establish a scalable and versatile approach to computational optics, with applications including real-time image processing, energy-efficient computing, biomedical imaging, high-fidelity holographic displays, and optical data storage, driving the advancement of intelligent optical processors.

We propose metasurface operators leveraging double-phase encoding and polarization multiplexing enable compact, all-optical analog computing for high-resolution image processing and complex holographic reconstruction.