Table 3. Suggested Roadmap for Optical Metasurfaces.

step	No. of units on the market (metasurface applications)	foundry	applications	expected year
phase 1	10 million unit	undisclosed foundry	early applications (fixed wavelength), i.e., near-infrared time-of-flight sensors, angular selectivity in 3D light field displays, 3D color pixels in security features	now
phase 2	100 million unit	general foundry	plug-in modules (fixed or discrete wavelength in VIS)	2023−2026
phase 3	500 million unit	growth of ecosystem, advances in multilayer foundry	replacement of existing applications (broadband continuous VIS)	2026−2030
phase 4	>1000 million unit	established	widely adopted metasurface products; totally new applications not imaginable with conventional optics	2030−future