Efficient dual-wavelength metasurface for second-order differential edge detection in the ultraviolet

Abstract

Metasurfaces for edge detection through spatial analog calculations have attracted much attention due to advantages such as a flexible design and small footprint. Up until now, most studies have focused on single-wavelength operation in the near-infrared or visible regions, while little work has been done in the ultraviolet band. It is of significance to explore metasurfaces for edge detection in the ultraviolet band for their great potential in high-resolution imaging and lithography. Here, we propose a dual-wavelength HfO2 metasurface for edge detection working at 273 nm and 293 nm, with 25% and 72% efficiency, respectively, controlled by the linear polarization of the incident light. The efficient dual-wavelength second-order differential calculation in the ultraviolet band of the metasurface has been confirmed by 1D signal and 2D image processing. It may find applications in the fields of computer vision and bioimaging.