  Metasurfaces, optics made from subwavelength-scale nanostructures, have been
limited to millimeter-sizes by the scaling challenge of producing vast numbers
of precisely engineered elements over a large area. In this study, we
demonstrate an all-glass 100 mm diameter metasurface lens (metalens) comprising
18.7 billion nanostructures that operates in the visible spectrum with a fast
f-number (f/1.5, NA=0.32) using deep-ultraviolet (DUV) projection lithography.
Our work overcomes the exposure area constraints of lithography tools and
demonstrates that large metasurfaces are commercially feasible. Additionally,
we investigate the impact of various fabrication errors on the imaging quality
of the metalens, several of which are unique to such large area metasurfaces.
We demonstrate direct astronomical imaging of the Sun, the Moon, and emission
nebulae at visible wavelengths and validate the robustness of such metasurfaces
under extreme environmental thermal swings for space applications.
