Single-Layer Diverse Chiral Metasurfaces Driven by Generative AI

Optical chirality has been extensively explored in chiral molecules, helical structures, and metasurfaces with bound states in the continuum. Attempts to attain chirality have mainly relied on human intuition and ideas. Here, we show various types of single-layer silicon-nanostructured metasurfaces exhibiting prominent circular dichroism (CD) containing perfect, broadband, and opposite CD responses at short near-infrared wavelengths. The designs were obtained based on a generative AI-assisted structural search for chiral metasurfaces, enabling a series of nonempirical structural searches beyond the boundary of human knowledge and experience. The physical mechanisms yielding the outstanding CD responses are elucidated from detailed insights into subwavelength electromagnetic dynamics in the single-layer metasurfaces. Furthermore, we experimentally demonstrate several metasurfaces. This type of single-layer thin CD metasurface serves as a key element in the development of compact optical-wave-manipulating devices at telecommunication bands.