大口径微纳结构平面光学元件的优化

Optimization of large-aperture micro-nano structure planar optical element

由微纳结构阵列构建的超构透镜体积小、质量轻,通过复合结构可实现多功能化设计,其口径一般为微米量级,对于诸如厘米级口径的超构透镜,其含有的微纳结构单元数量达到数十亿个。如果采用逐一建模的方式绘制这些微纳结构,必然导致版图文件过大,以至图形绘制时间长以及版图无法打开。为了解决此问题,基于版图设计软件L-Edit提出环状布局的超构透镜设计方法,采用二进制与库调用相结合的方法绘制超构透镜每个圆环中构建单元阵列,从而实现大口径超构透镜版图文件的有效压缩。研究结果表明:设计的超构透镜实现了亚波长聚焦;针对口径为50 mm的超构透镜,利用本文提出的版图绘制压缩方法,其版图文件大小为176 MB,远小于采用逐一建模绘制方式生成的版图文件(3.70 TB),实现了大口径超构透镜版图设计文件海量数据的高效压缩,从而保证了大口径超构透镜元件设计的可制造性。

The metalens constructed by the micro-nano structure array is not only small and lightweight,but also has a multi-functional design that can be realized through a composite structure.The existing metalens diameters are generally in the order of micrometers.For a metalens such as a centimeter-level diameter,the number of micro-nano structure units contained in it can reach billions.If these massive micro-nano structures are drawn by modeling them sequentially,the layout file will inevitably be too large,such that the drawing time is so long that the layout cannot be opened.To solve this problem,this study proposes a circular layout metalens design method based on the layout design software L-Edit.This method uses binary coding to divide the metalens into blocks to compress the layout file.Numerical simulation results show that the designed metalens achieves sub-wavelength focusing.For the 50 mm diameter metalens,the layout file size obtained using the proposed layout drawing method is 176 MB.This is much smaller than the layout file size(3.70 TB)generated by the one-by-one modeling and drawing method.This study proves that an efficient compression of massive data of a large-aperture metalens in the layout design ensures the manufacturability of the design of large-aperture metalens elements.