Published in the journal Light: Science & Applications, a groundbreaking study by a research team from the Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, introduces a revolutionary design approach for fixed-height concentric-ring metalenses. This innovative work addresses the increasing demand for metalenses with diameters reaching the order of 105λ, offering advancements in the field of optics. The traditional manufacturing of metalenses often faces challenges due to the vast amount of layout data required, leading to high processing costs. To overcome this, the researchers proposed a design method that utilizes subwavelength 2D building units, classified based on different topological structures. These units are then employed to construct concentric-ring metalenses with fixed heights, inheriting the advantages of building-block-array metalenses in polarization-independent focusing scenarios.
In the research process, the team employed genetic algorithms and deep learning to construct targeted optimization models, aiming to obtain optimal solutions that meet manufacturing process requirements. However, when dealing with metalenses with diameters of several hundred wavelengths or more, the computational demands were extremely high, both in terms of power and time. To solve this, the researchers innovatively used 2D subwavelength building units to splice the cross-section of the concentric-ring metalens, significantly reducing the computational complexity.
The results demonstrated the effectiveness of the proposed method. The concentric-ring metalenses exhibited excellent optical performance, with high focusing efficiency and insensitivity to geometric parameters. Specifically, the research team fabricated a metalens with a diameter of 46.8mm, thickness of 960nm, and feature size of 120nm. Tests conducted on this metalens showed that it could correct monochromatic aberrations in a field of view of 20°, making it the largest metalens diameter (nearly 2 inches) for full-field monochromatic aberration correction meta-camera reported so far.
The development of these fixed-height concentric-ring metalenses holds great significance for various applications. They offer the potential to replace traditional optical lenses, significantly enhancing the optical performance of imaging systems. Additionally, the proposed design method provides a new approach for the manufacture of large-diameter metalenses, paving the way for further advancements in the field of optics.
In conclusion, the study presents a design method for fixed-height concentric-ring metalenses. By utilizing subwavelength 2D building units and advanced optimization models, the researchers successfully overcame the challenges associated with the manufacture of large-diameter metalenses. This work not only demonstrates the effectiveness of the proposed method but also holds promise for various optical applications.
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