Single-Layer Bayer Metasurface via Inverse Design
Jiahao Li, Qiang Zhang, Hui Yang, Ting Lei, Luping Du, Xianyou Wang, Jing Bu, Qinmiao Chen, Yilin Liu, Zhenwei Xie, Xiaocong Yuan
Abstract
Developing color image sensors with miniaturization and high-resolution as goals brings challenges to conventional color filters that, by absorbing out-of-band light, have low light transmission resulting from light separation. The emergence of nanophotonic color splitters with full-band transmission offers an alternative solution. For the Bayer array imaging sensor, we demonstrate numerically and experimentally a nanophotonic color splitter via introducing an optimization algorithm based on path information in inverse design. The device has a total transmission efficiency of 80% across the entire visible spectrum. It is capable of sorting normal incident red, green, and blue components into their respective target imaging regions with peak efficiencies of up to 58.3%, 52.6%, and 69.6%, respectively, which are significantly higher than that of conventional color filters (∼30%). We fabricated the device with a Bayer cell footprint of 1.6 × 1.6 μm2 and in experiments obtained its intensity profiles and spectrum properties. The demonstration is an ultracompact Bayer nanophotonic color splitter with a simple single-layer 2D structure.