非エルミート型メタサーフェスにおけるトポロジカル保護の破壊による近接した波長多重化の解明

Wavelength-multiplexed metasurfaces enable precise, independent light control at multiple wavelengths within a single platform, demonstrating significant potential for compact applications in imaging, optical communications, and information processing. Exceptional points (EPs) in non-Hermitian systems have garnered considerable interest in optics and physics owing to their unique phase characteristics in parameter space. Prior approaches to wavelength-multiplexing metasurface design employ neural networks, polarization manipulation, or spatial division. In contrast, this work leverages the wavelength dependence of EPs to implement wavelength multiplexing with narrow channel spacing under a single polarization state. By adopting distinct paths in parameter space, we achieve customized wavelength-dependent phase manipulations. As a practical demonstration, we independently manipulate two wavelengths to generate orbital angular momentum (OAM) beams with distinct topological charges (with a wavelength spacing of 38 nm), and customized holographic patterns at shorter wavelength spacing (18 nm).