中山大学王雪华团队通过在阶梯式相位色散补偿层上复用元原子实现高性能消色差平面透镜。2025年3月5日，《光：科学与应用》杂志发表了这一成果。

几十年来，平面光学因其操纵光波特性的灵活性而引起了人们的兴趣，这使得笨重的光学组件能够小型化为集成的平面组件。消色差平面透镜的最新进展在各个领域显示出有前景的应用。然而，对于具有高数值孔径的消色差平面透镜来说，同时实现宽带宽和扩大孔径尺寸是一个重大挑战。

研究组提出了在逐步相位色散补偿（SPDC）层上对元原子进行区分复用，以解决上述挑战。原则上，通过增加SPDC层中心和边缘区域之间的光学厚度差，可以自由扩大孔径尺寸，而不受消色差带宽的限制。SPDC层还用作基板，使器件更薄。实验实现了两个厚度为500 nm、带宽为650-1000 nm的消色差平面透镜：一个数值孔径为0.9，半径为20.1µm，另一个数值孔径为0.7，半径为30.0µm。

据研究组所知，它们是迄今为止报道的具有最高数值孔径、最大孔径和最薄厚度的宽带消色差平面透镜。白光照明也证明了1.10µm分辨率的显微成像，超过了之前报道的消色差金属透镜和多级衍射透镜所达到的任何分辨率。这些前所未有的性能标志着平面透镜在实际应用中迈出了重要的一步。

附：英文原文

Title: High-performance achromatic flat lens by multiplexing meta-atoms on a stepwise phase dispersion compensation layer

Author: Lin, Jingen, Chen, Jinbei, Zhang, Jianchao, Liang, Haowen, Li, Juntao, Wang, Xue-Hua

Issue&Volume: 2025-03-05

Abstract: Flat optics have attracted interest for decades due to their flexibility in manipulating optical wave properties, which allows the miniaturization of bulky optical assemblies into integrated planar components. Recent advances in achromatic flat lenses have shown promising applications in various fields. However, it is a significant challenge for achromatic flat lenses with a high numerical aperture to simultaneously achieve broad bandwidth and expand the aperture sizes. Here, we present the zone division multiplex of the meta-atoms on a stepwise phase dispersion compensation (SPDC) layer to address the above challenge. In principle, the aperture size can be freely enlarged by increasing the optical thickness difference between the central and marginal zones of the SPDC layer, without the limit of the achromatic bandwidth. The SPDC layer also serves as the substrate, making the device thinner. Two achromatic flat lenses of 500nm thickness with a bandwidth of 650–1000nm are experimentally achieved: one with a numerical aperture of 0.9 and a radius of 20.1μm, and another with a numerical aperture of 0.7 and a radius of 30.0μm. To the best of our knowledge, they are the broadband achromatic flat lenses with highest numerical apertures, the largest aperture sizes and thinnest thickness reported so far. Microscopic imaging with a 1.10μm resolution has also been demonstrated by white light illumination, surpassing any previously reported resolution attained by achromatic metalenses and multi-level diffractive lenses. These unprecedented performances mark a substantial step toward practical applications of flat lenses.

DOI: 10.1038/s41377-024-01731-8

Source: https://www.nature.com/articles/s41377-024-01731-8