Switchable imaging between edge-enhanced and bright-field based on a phase-change metasurface

Edge-enhanced imaging and bright-field imaging extract different morphological information from an object, and hence a system capable of switching dynamically between them is of vital importance for various applications. By incorporating an elaborately designed meta-device with a 4f imaging system, we demonstrate dynamic switching between 2D edge-enhanced imaging and bright-field imaging. The dynamically switchable characteristic results from the composed phase-change material meta-atoms, which are optimized to provide two independent phase profiles in amorphous and crystalline states. For dynamically switchable imaging, the meta-device functions as either a high-pass or a low-pass filter in the Fourier frequency spectrum, relying on its phase state. In addition, the dynamically switchable imaging is polarization independent. The proposed meta-device owns ultra-thin architecture and polarization-insensitive dynamically switchable functionality, holding potential applications in integrated biomedical imaging and defect detection.