Dynamically switchable edge-detection and bright-field imaging based on a phase-change nonlocal metasurface.

Optical metasurfaces offer significant advantages in enhancing the speed, efficiency, and miniaturization of imaging systems. However, most existing metasurfaces are limited to static functionalities and lack reconfigurability, which is a key feature for practical applications in dynamic environments. In this work, we demonstrate a reconfigurable optical metasurface capable of switching between two distinct imaging functions (edge detection and bright-field imaging) within the visible spectrum. This reconfigurability is achieved by tuning the phase transition of antimony sulfide (SbS), which controls the angular dependence of the magnetic dipole resonance. The phase transition of SbS from the amorphous phase to the crystalline phase enables different optical transfer functions, achieving high-performance imaging with a numerical aperture of 0.42, isotropic second-order differentiation, and high-resolution imaging, respectively. This approach allows for functional switching on a single surface, opening up possibilities for applications in medical imaging, optical sensing, and microscopy.