Multi-directional plasmonic splitter and polarization analyzer based on the catenary metasurface

Owing to the unique properties of strongly confined and enhanced electric fields, surface plasmon polaritons (SPPs) provide a new platform for the realization of ultracompact plasmonic circuits. However, there are challenges in coupling light into SPPs efficiently and subsequently routing SPPs. Here, we propose a multi-directional SPPs splitter and polarization analyzer based on the catenary metasurface. Based on the abundant electromagnetic modes and geometric phase modulation principle of catenary structure, the device has realized high efficiency beam splitting for four different polarization states ( x -polarization, y -polarization, LCP and RCP). The central wavelength of the device is 632 nm and the operation bandwidth can reach 70 nm (585-655 nm). Based on the phenomenon of SPPs beam splitting, we present a prototype of a polarization analyzer, which can detect the polarization state of incident light by adding photodetector with light intensity logic threshold in four directions. Moreover, by combining this device with dynamic polarization modulation techniques, it is possible to be served as a router or switch in integrated photonic circuits.