Fig. 4: Schematic diagrams of fabrication process for metasurfaces using.
From: Review for optical metalens based on metasurfaces: fabrication and applications
a the conventional top-down etching-based method and (b) the novel bottom-up deposition method (nanostructures are defined using patterned EBR), no proportional relationship. c Fabrication process for freestanding bilayer metasurfaces. Reprinted with permission from ref. 140. Copyright 2025 Springer Nature
