Fig. 3: Fabrication methods and images of fabricated metalenses via the NIL technique.

a Schematic of the fabrication process of facile nanocasFabrication methods and images of fabricated metalenses via the NIL technique.Fabrication methods and images of fabricated metalenses via the NIL techniqueFabrication methods and images of fabricated metalenses via the NIL techniqueting. b Schematic of the fabrication process based on nanocomposite material. c Schematic of the fabrication process with stamp fabrication (spin coating and thermal cure) and imprinting (spin coating, stamp placement, UV cure and stamp release) to produce tens of thousands of devices. d Schematic of the fabrication process based on the ALD technique. e Schematic of the fabrication process for twisted bilayer metadevice, the top layer is reversal nanoimprinted onto the bottom layer with a twist angle. f Schematic of the fabrication process based on wet etching technique. g Schematic of the fabrication process with tape-assisted, which enables duplication of residual layer-free meta-atoms. h SEM image shows the fabricated high-contrast grating with the TiO₂-SiO₂ bilayer nanopillars. i SEM image shows the fabricated meta-polarizer with SiN_x metagrating, buffer layer, and Al metagrating. j SEM image shows the fabricated metalens with high AR TiO₂ PER nanopillars with different sizes. k SEM image shows the cross-section of the fabricated bilayer metadevice with an intermediate layer. Photographs of replicated metasurfaces on various substrates: glass substrate (l), curved substrate (m), and flex substrate (n). Inset: the top view of metasurfaces. Photographs of replicated metalenses on various substrates: glass substrate (o), flex substrate (p), convex substrate (q), and concave substrate (r). a, l–n Reprinted with permission from ref. ¹⁰¹. Copyright 2019 American Chemical Society. b Reprinted with permission from ref. ¹⁰³. Copyright 2021 American Chemical Society. c–j Reprinted with permission from ref. ¹⁰⁴. Copyright 2021 American Chemical Society. d Reprinted with permission from ref. ¹⁰⁵. Copyright 2023 Springer Nature. e–k Reprinted with permission from ref. ¹⁰⁷. Copyright 2023 De Gruyter. f, o–r Reprinted with permission from ref. ¹⁰⁸. Copyright 2023 Springer Nature. g Reprinted with permission from ref. ¹¹². Copyright 2025 John Wiley and Sons. h Reprinted with permission from ref. ⁹⁹. Copyright 2014 American Vacuum Society. i Reprinted with permission from ref. ⁸⁴. Copyright 2016 Optical Society of America