A wide-field-of-view metalens array for CMOS image sensors' conical light focusing.

• We provided discussions on the research of CMOS sensors, and the method to enhance the focusing efficiency of photo-sensitive pixels. • Conical light field can be compensated by using a concave lens phase while employing convex metalens phase distribution for parallel beams. • Our metalens design have potential application in integration of the metalens with CMOS sensors. Microlens array combined with CMOS sensors have recently been the subject of intensive research due to their ability to significantly enhance imaging sensitivity. However, existing microlens arrays suffer from a limited field-of-view, necessitating complex lens assemblies that increase system cost, size and weight. In this study, we present a novel approach utilizing a single layer metalens array composed of low loss and high-index α-Si materials. The metalens array was designed using a phase compensation method to efficiently focus conical light with arbitrary cone angles onto the center pixels of the CMOS sensor. Theoretical analysis demonstrates that the metalens is capable of focusing ± 20° conical light with an impressive efficiency of 83.6 %, which can be extended to arbitrary cone angles. Experimental results reveal a measured focusing efficiency of 73 % under an incidence angle of ± 8.3° for conical light, representing an improvement of 8 % compared to parallel light incidence. This research presents a promising solution for wide-field-of-view metalens arrays in integrated CMOS imaging systems. [ABSTRACT FROM AUTHOR]