大视场级联超表面透镜成像系统

    Wide field-of-view cascaded metasurface imaging system

    • 摘要: 在现代先进光学系统中,对同时具备大视场角与高分辨率成像能力的成像单元的需求日益迫切。传统光学设计在实现系统紧凑化时常面临视场与像质的固有矛盾。超表面作为一种二维人工结构,为光学系统的小型化、集成化与功能定制化提供了革命性途径。然而,单层超透镜普遍受限于有限的视场。为此,设计了一种基于双曲相位与二次相位拼接的双层级联超透镜结构。该相位拼接方法能够改善超透镜在正入射和斜入射时的聚焦性能,有效地扩展了成像视场并提升像质。在此基础上,进一步引入第2层超表面构成级联系统,该级联结构不仅能继承并增强拼接相位对大视场的校正能力,还可通过两层相位分布的协同优化,抑制单层设计中难以避免的高阶衍射与残余像差,从而在实现高达100°大视场成像的同时,显著提升聚焦光斑的质量与能量集中度。这种设计方法可为解决紧凑型光学系统的大视场成像难题提供一种有效方案,在车载感知、广角监控等需要宽视野精准成像的应用场景中具有发展潜力。

       

      Abstract: 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.

       

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