Dielectric Vectorial Metalens Enables Simultaneous Isotropic 2D and Direction‐Tunable 1D Edge Detection Over the Visible

ABSTRACT

Edge detection is a fundamental operation in image processing, underpinning diverse applications in biomedical imaging, industrial inspection, and autonomous navigation. While metasurface‐based schemes offer compact alternatives to conventional bulky‐optics counterparts, most existing implementations are restricted to either isotropic two‐dimensional (2D) or fixed‐orientation one‐dimensional (1D) edge detection. Here, we present a vectorial metalens that unifies isotropic 2D and direction‐tunable 1D modes within a single device. The device integrates S‐waveplate modulation with a hyperbolic phase profile to engineer polarization‐dependent point spread functions, thus allowing dynamic switching between 2D and 1D modes by simply tuning the illumination polarization. We implement the metalens using tantalum pentoxide (Ta ₂ O ₅ ), a low‐loss and fabrication‐friendly dielectric metasurface platform for the visible. The device operates across a broad visible spectrum and achieves edge detection resolution better than 4.4 µm in both modes. We further validate its performance on both amplitude‐type and phase‐type objects, showing that the isotropic 2D mode captures global object contours, while the tunable 1D mode selectively enhances features along user‐defined directions. This work establishes a compact, lightweight, and multifunctional platform for real‐time all‐optical edge detection that unifies its two fundamental modes, opening new avenues in advanced bioimaging, intelligent sensing, and machine vision.