Wide field-of-view cascaded metasurface imaging system

In modern advanced optical systems, there are growing requirements for imaging units that simultaneously offer a wide field of view and high-resolution imaging. Traditional optical design often encounters an inherent trade-off between field of view and image quality for achieving miniaturized optical system. Metasurfaces, as two-dimensional artificial structures, can achieve miniaturization, integration, and functional customization of optical systems. However, single-layer metalenses are generally limited by small field of view. Therefore, a bilayer cascaded metalens structure based on stitching of hyperbolic and quadratic phase profiles was designed. The phase stitching method improved the focusing performance of metalens under both normal and oblique incidence, effectively expanding imaging field of view and enhancing image quality. On this basis, a second metasurface layer was further introduced to form a cascaded system. This cascaded structure inherited and enhanced wide-field correction capability of stitched phase. Moreover, through co-optimization of two-layer phase distributions, it further suppressed higher-order diffraction and residual aberrations inherent in single-layer designs. As a result, while achieving wide-field imaging with a field of view of up to 100°, it significantly improved the quality and energy concentration of focused spot. This design approach provides an effective solution to achieve wide-field imaging in compact optical systems. It holds potential for applications such as vehicular perception and wide-angle surveillance, which require broad-field and high-precision imaging.