Bandwidth bounds for wide-field-of-view dispersion-engineered achromatic metalenses

Optical systems with wide field-of-views (FOV) are crucial for many applications such as high performance imaging, optical projection, augmented/virtual reality, and miniaturized medical imaging tools. Typically, aberration-free a FOV is achieved by stacking multiple refractive lenses (as in “fisheye” lens), adding to the size weight of system. Single metalenses designed have potential replace these bulky and, moreover, they may be dispersion engineered spectrally broadband operation. In this paper, we derive fundamental bound on spectral bandwidth dispersion-engineered wide-FOV achromatic metalenses. We show that relatively large numerical aperture (NA), there tradeoff between maximum achievable FOV; interestingly, however, reduction saturates beyond certain depends NA metalens. These findings provide important information insights design future flat lenses.