基于光场拼接的消色差超透镜设计

Achromatic Metalens Design based on Light Field Stitching

摘要:

红外成像技术被广泛应用于医学诊断、光谱学、分子传感等领域,近年来,超透镜技术为红外成像提供了一个小型化和集成化的平台。由于超透镜固有色散的存在,极大地阻碍了其在红外成像中的应用。而目前设计消色差超透镜的主流方法是先对超透镜进行仿真,然后分析相关性能参数,这种传统方法需要大量的时间。为了解决这一问题,文章采用光场拼接的技术,结合粒子群算法,设计了一个直径为100μm,工作波段在3.7~4.8μm范围内的全硅介质消色差超透镜,其计算的有效焦距为219.01μm,离焦系数为1.87%,最高聚焦效率为49.3%。并用Lumerical FDTD软件对所设计的超透镜进行仿真验证,将仿真结果和拼接结果在焦距、离焦系数、计算时间、半高全宽、聚焦效率和调制传递函数等方面进行了系统地对比,从而验证了光场拼接技术的可行性和正确性。这种方法可以扩展到其他波段,并为设计更大尺寸的超透镜提供了一个新的思路。

Abstract:

Infrared imaging technology is widely used in fields such as medical diagnosis, spectroscopy, and molecular sensing. In recent years, metalens technology has provided a miniaturized and integrated platform for infrared imaging. However, the inherent dispersion of metalenses greatly hinders their application in infrared imaging. The current mainstream method for designing achromatic metalenses involves simulating the metalens and then analyzing relevant performance parameters, which is time-consuming. To address this issue, this study utilizes the field stitching technique, combined with a particle swarm optimization algorithm, to design a full-silicon achromatic metalens with a diameter of 100μm, operating in the range of 3.7~4.8μm. The calculated effective focal length of the designed metalens is 219.01μm, with a coefficient of variation of 1.87% and a maximum focusing efficiency of 49.3%. The designed metalens was simulated and validated using Lumerical FDTD software. A systematic comparison between the simulation results and the stitching results was conducted in terms of the focal length, coefficient of variation, computational time, full width at half maximum, focusing efficiency, and modulation transfer function, confirming the feasibility and accuracy of the field stitching technique. This method can be extended to other wavelength bands and provides a novel approach for designing larger metalenses.