Achieving high numerical aperture near-infrared imaging based on an ultrathin cylinder dielectric metalens

Artificial subwavelength dielectric meta-lens (ML), realization of ultrathin and light-weight, provides a potential candidate to replace traditional bulky curved lens with high image quality. A ML with 1.5 mm in diameter having numerical aperture NA ~ 0.60 at the near-infrared wavelength λ = 0.94 μm was designed by finite-difference timedomain (FDTD) method with speeding up optimization of MLs’ scheme by deep neural network (DNN) model. Additionally, an ultra-thin high NA ML was achieved by cost effective semiconductor manufacturing technology. The fabricated ML can focus an incident light down to a spot as small as ~ 5.2 μm with high optical efficiency of ~88.4% (focusing efficiency achieved 23.7%). We also provided efficient MLs’ semiconductor manufacturing technology for the development of optical device in the near-infrared image technology.