Subwavelength periodic nanostructure-based circular polarizer for optical communications

There exists an inherent trade-off between structural complexity and the polarization extinction ratio (PER) in metasurface-based circular polarizers. In this work, we propose a single-layer Z -shaped chiral aluminum metasurface that achieves a high PER, enabling efficient circular polarization measurement at the optical communication wavelengths (1310–1550 nm). By synergistically tuning the subwavelength geometric asymmetry and localized surface plasmon resonance effects, our design not only overcomes the limitations of conventional multilayer structures but also significantly enhances the chiral light–matter interaction. The proposed metasurface exhibits excellent polarization selectivity in the target wavelength band, with a peak PER on the order of 5×10 4 , and its peak working wavelength can be actively controlled via geometric parameters.