Tunable edge and depth sensing via phase-change nonlocal metasurfaces

TL;DR

This paper introduces a tunable nonlocal metasurface that can simultaneously extend depth-of-field and enhance edges in images through wavelength control, enabling real-time 3D imaging and feature extraction.

Contribution

It presents a novel phase-change metasurface design that combines wavefront shaping and spatial filtering for integrated depth and edge sensing.

Findings

Achieved continuous wavelength tuning over 100 nm with Sb₂S₃

Demonstrated simultaneous depth extension and edge enhancement in a single shot

Enabled broadband spectral adaptability for real-time imaging applications

Abstract

Performing simultaneous depth-of-field (DoF) extension and edge enhancement within a single optical element remains a fundamental challenge in advanced imaging. Here, we propose a wavelength-tunable nonlocal Huygens' metasurface capable of simultaneously extracting depth and edge features of images in a single-shot exposure. Using the selective polarization response of the Huygens' metasurfaces, the circularly polarized converted component undergoes geometric phase modulation for wavefront shaping to extend the DoF, while the non-converted component acts as a spatial frequency filter to enhance edge contrast. The integration of a phase-change material, Sb$_{2}$S$_{3}$, enables continuous tuning of the resonance wavelength across a range of 100 nm by modulating its refractive index, granting the system excellent broadband spectral adaptability. This work offers a novel and compact solution for real-time depth sensing and feature extraction in applications such as autonomous navigation and biomedical imaging.