Optical performance of synthetic aperture metalens based on hybrid unit-cells

In this paper, we introduce a metalens with a hybrid unit-cell arrangement that operates at a wavelength of 0.94 μm. The metalens consists of 0.8 μm unit-cells on the inner and 0.4 μm unit-cells on the outer. The transmittance of 0.8 μm and 0.4 μm unit-cells are about 0.5 and 1, respectively. Therefore, the proposed metalens with hybrid unit-cells, behaving like a synthetic aperture lens, suppresses the low spatial frequency signal and enhances the high spatial frequency one. As a result, the proposed metalens with hybrid unit-cells presents a higher spatial resolution than that with an identical unit-cell size and holds higher transmittance than that of a conventional synthetic aperture lens. Moreover, we comprehensively discuss the optical performance and limitations of pixelate metalens and expand the application prospects of synthetic aperture metalenses in optical imaging.