Polarization-independent edge detection based on the spin–orbit interaction of light

Abstract

In previous edge detection schemes based on the spin-orbit interaction of light, the direction and intensity of the edge-enhanced images are influenced by the incident polarization state. In this study, we develop an edge detection strategy that is insensitive to changes in both the incident polarization and the incident angle. The output intensity and transfer function remain entirely impervious to changes in incident polarization, being explicitly formulated as functions of the incident angle, specifically in terms of cot2⁡θ i and cot⁡θ i , respectively. This behavior is attributed to the opposing nature of the polarization components E~ r H−H and E~ r V−V in the x-direction after undergoing mapping through the Glan polarizer, while the sum of polarization components E~ r H−V and E~ r V−H in the y-direction can be simplified to terms independent of incident polarization. Furthermore, we propose a metasurface design to achieve the required optical properties in order to realize the derived edge detection scheme.