中红外波长超构透镜最优焦距的研究

Research on the optimal focal length of metalens in the mid infrared band

本文拟设计一种工作在中红外波长偏振不敏感的透射式超构透镜。该设计使用二氧化硅作为衬底,硅作为介质材料,超构透镜半径为100μm,最优焦距为302μm,聚焦效率为70.72%,其仿真焦距与理论计算仅有0.0013%的误差。同时以焦距误差最小值为参考,设计了多个不同半径的超构透镜,并得到了最优焦距、数值孔径、聚焦效率等数据,提高了后续基于相同结构设计超构透镜的效率。其设计方法为计算中红外超构透镜最优焦距提供了思路,为提高中红外超构透镜效率提供了技术支持。

In this paper,a transmissive metalens operating in the mid infrared band with polarization insensitivity is designed.Using silicon dioxide as the substrate and silicon as the dielectric material,the metalens has a radius of 100μm,an optimal focal length of 302μm,a focal efficiency of 70.72%,and a simulated focal length with only 0.0013%error from the theoretical calculation.Taking the minimum value of the focal length error as a reference,several metalens with different radii were designed,and the data of optimal focal length,numerical aperture,and focusing efficiency are obtained,which improved the efficiency of the subsequent design of metalens based on the same structure.The design method provides ideas for calculating the optimal focal length of metalens,and offers technical support for improving the efficiency of the mid infrared superstructured lens.