State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics, Sun Yat-Sen University, Guangzhou 510275, China.
São Carlos School of Engineering, Department of Electrical and Computer Engineering, University of São Paulo, São Carlos, SP 13566-590, Brazil.
Nano Lett. 2022 May 25;22(10):3969-3975. doi: 10.1021/acs.nanolett.2c00486. Epub 2022 May 4.
Chromatic aberration is a major challenge faced by metalenses. Current methods to achieve broadband achromatic operation in metalenses usually suffer from limited size, numerical aperture, and working bandwidth due to the finite group delay of meta-atoms, thus restricting the range of practical applications. Multiwavelength achromatic metalenses can overcome those limitations, making it possible to realize larger numerical aperture (NA) and sizes simultaneously. However, they usually require three layers, which increases their fabrication complexity, and have only been demonstrated in small sizes, with low numerical aperture and modest efficiencies. Here, we demonstrate a 1 mm diameter red-green-blue achromatic metalens doublet with a designed NA of 0.8 and successfully apply the metalens in a digital imaging system. This work shows the potential of the doublet metasurfaces, extending their applications to digital imaging systems such as digital projectors, virtual reality glasses, high resolution microscopies, etc.
色差是超表面透镜面临的主要挑战。目前在金属超表面中实现宽带消色差的方法通常由于亚波长结构的有限群延迟而受到尺寸、数值孔径和工作带宽的限制，从而限制了实际应用的范围。多波长消色差金属超表面可以克服这些限制，使得同时实现更大的数值孔径（NA）和尺寸成为可能。然而，它们通常需要三个层，这增加了它们的制造复杂性，并且仅在小尺寸、低数值孔径和中等效率的情况下得到了证明。在这里，我们展示了一个直径为 1 毫米的红绿蓝消色差金属透镜对，设计的数值孔径为 0.8，并成功地将金属透镜应用于数字成像系统中。这项工作展示了双金属超表面的潜力，将它们的应用扩展到数字成像系统，如数字投影仪、虚拟现实眼镜、高分辨率显微镜等。
