Polarization-multiplexing metasurface for vectorial optical field demultiplexing and detection on higher-order Poincaré sphere

Abstract

The emergence of vectorial optical fields (VOFs) featuring polarization singularities has introduced a new dimension to high-capacity optical communication. Cylindrical vector beams (CVBs) with VOFs play a pivotal role in enhancing multiplexing capabilities due to their transmission stability and resilience to turbulence. Straightforwardly and efficiently demultiplex CVBs with minimal crosstalk remain challenging for practical applications. This study proposes a single-layer dielectric metasurface for demultiplexing CVBs at telecommunications wavelengths. By leveraging polarization multiplexing and adjusting the rotation angle of customized metasurface units, effective spatial separation of CVB pairs is demonstrated. Furthermore, the methodology extends to demultiplexing multiple CVB pairs using interleaved unit cells set at distinct customized angles. The demultiplexing of 12-channel CVBs and their subsequent focusing into Gaussian spots were successfully demonstrated as a proof of concept. This work holds the significant potential for complex structured light manipulation and high-capacity optical communications.