Metalenses consist of nanostructures that locally control the optical phase. They offer many degrees of freedom for manipulating a wavefront, which gives a number of advantages over bulk lenses, such as the straightforward elimination of spherical aberrations and an ultrathin dimension. Here, we compare the phase profiles of metalenses made of different dielectric materials and note the advantage of high refractive index materials. Higher refractive index materials such as silicon afford more degrees of freedom in terms of design and fabrication and are the basis for high-performance metalenses, even in the visible. Nevertheless, the imaging performance of single-element metalenses is still limited by coma and chromatic aberrations. This limitation is exacerbated by high numerical apertures and large areas. We review the challenges and trade-offs between numerical aperture, field of view, coma, chromatic aberration, and size. We also evaluate different phase engineering approaches to address these problems. We believe this review will help guide future developments in high-performance metalenses toward wide-field and high-resolution imaging, enabling scientific high-end miniature imaging systems.

中文翻译：

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高性能metalense：数值孔径，像差，色度和折衷方案

Metalenses由局部控制光学相位的纳米结构组成。它们为操纵波前提供了许多自由度，与大块透镜相比，具有许多优势，例如直接消除球差和超薄尺寸。在这里，我们比较了由不同介电材料制成的金属材料的相位分布，并注意到了高折射率材料的优势。诸如硅之类的较高折射率的材料在设计和制造方面提供了更大的自由度，并且即使在可见光范围内也是高性能metalense的基础。尽管如此，单元素金属镜的成像性能仍然受到彗形像差和色差的限制。高数值孔径和大面积加剧了这一局限性。我们回顾了数值孔径，视野，彗形像差，色差和尺寸之间的挑战和取舍。我们还评估了解决这些问题的不同阶段工程方法。我们相信，这次审查将有助于指导高性能金属传感器在宽范围和高分辨率成像方面的未来发展，从而实现科学的高端微型成像系统。