Reconfigurable Metasurface for Enhanced Imaging and Image Denoising

Abstract

Optical metasurfaces (flat optics) allow unprecedented control over light, enabling multi-dimensional light modulation. We propose a non-local metasurface hosted by phase change material Sb₂S₃ for tunable image processing. It supports three imaging modalities: bright field, edge detection, and image denoising for intensity noise, functioning as diffractive image denoisers. The Structural Similarity Index Measure is used as a metric between the input noisy image and the denoised image. By tuning the phase of Sb₂S₃, its refractive index changes, effectively shifting the electromagnetic modes and resulting in these imaging modalities by providing the required optical transfer function (OTF). We optimized the metasurface design to achieve the required OTF and performed simulations on complex images with many corners and 2-dimensional structures. We introduced salt and pepper noise into the input image and conducted simulations to evaluate performance. We discuss the shape of the OTF for image denoising applications and its adaptation for simultaneous image denoising and edge detection, both of which involve high spatial frequencies of the object. Our dynamically tunable metasurface platform can seamlessly integrate with standard coherent imaging systems, enabling versatile operations on the input image.