Breakthrough in Spin Photonics: Folded-Path Metasurface Overcomes Bandwidth Limits

In a groundbreaking development, researchers from China have introduced a folded-path metasurface platform that significantly advances the field of spin photonics. This innovative technology enables independent dispersion and phase control of two opposite spin states, overcoming the longstanding challenge of bandwidth constraints in optical manipulation. Published in Light Science & Applications, the study showcases the platform's ability to achieve achromatic focusing, spin Hall effects, and the generation of spatiotemporal vector optical fields with a single metasurface. This breakthrough, detailed in a paper, opens new avenues for dynamic light-matter interactions and the development of next-generation spin-photonic devices, marking a paradigm shift from traditional metasurface approaches.

The research, conducted by the National Key Laboratory of Optical Field Manipulation Science and Technology, highlights the potential for compact spin-multiplexing devices in broadband polarization optics, information encoding, and spatiotemporal optical field manipulation. Supported by the National Key Research and Development Program of China and the National Natural Science Foundation of China, this study not only demonstrates the first realization of broadband achromatic photonic spin Hall effect but also the generation of spatiotemporal vector optical fields using a single metasurface, without the need for structural geometry modifications.