CMOS-compatible a-Si metalenses on a 12-inch glass wafer for fingerprint imaging

Metalenses made of artificial sub-wavelength nanostructures have shown the capability of light focusing and imaging with a miniaturized size. Here, we report the demonstration of mass-producible amorphous silicon metalenses on a 12-inch glass wafer via the complementary metal-oxide-semiconductor compatible process. The measured numerical aperture of the fabricated metalens is 0.496 with a focusing spot size of 1.26 mu m at the wavelength of 940 nm. The metalens is applied in an imaging system to test the imaging resolution. The minimum bar of the resolution chart with a width of 2.19 mu m is clearly observed. Furthermore, the same system demonstrates the imaging of a fingerprint, and proofs the concept of using metalens array to reduce the system size for future compact consumer electronics.