Large-scale achromatic flat lens by light frequency-domain coherence optimization

Flat lenses,including metalens and diffractive lens,have attracted increasing attention due to their ability to miniaturize the imaging devices.However,realizing a large scale achromatic flat lens with high performance still remains a big challenge.Here,we developed a new framework in designing achromatic multi-level diffractive lenses by light coherence optimization,which enables the implementation of large-scale flat lenses under non-ideal conditions.As results,a series achromatic polymer lenses with diameter from 1 to 10mm are successfully designed and fabricated.The subsequent optical characterizations substantially validate our theoretical framework and show relatively good performance of the centimeter-scale achromatic multi-level diffractive lenses with a super broad bandwidth in optical wavelengths(400-1100 nm).After comparing with conventional refractive lens,this achromatic lens shows significant advantages in white-light imaging performance,implying a new strategy in developing practical planar optical devices.