Shaping light with multilayer metasurfaces: Design, fabrication, and applications

Abstract Optical metasurfaces are planar arrays of engineered subwavelength nanostructures, and have emerged as a revolutionary platform for manipulating the light-matter interactions. Recently, vertical stacking of two or more metasurface layers has become a powerful and universal strategy for multifunctional optical field manipulation. By introducing additional degrees of freedom, such as interlayer spacing, twist angle, and lattice mismatch, multilayer metasurfaces enable unprecedented optical responses without altering the constituent materials or unit cell geometries. This structural versatility has significantly accelerated the advancement of multifunctional and reconfigurable photonic devices. This review provides a comprehensive overview of multilayer metasurfaces operating in the visible to near-infrared regime, with an emphasis on their physical mechanisms, structural evolution, fabrication methodologies, and applications. We summarize some recent breakthroughs across several frontier applications, including high-resolution imaging, optical information encoding, biosensing, and laser emission enhancement. In addition, we identify key challenges in material selection, inverse design, and scalable integration, and discuss future directions toward dynamic, large-area, and intelligent metasurface systems. Finally, we outline the promising role of multilayer metasurfaces in next-generation photonic platforms, smart imaging technologies, and all-optical information processing systems.