Abstract

In this paper, unlike many researches that focus on beam splitters based on gratings with symmetrical structures, an asymmetric grating with double-groove structure is proposed. Based on the double-groove grating, multi-port beam splitters including dual-port, three-port, and four-port, under normal incidence working at terahertz frequency are designed for both transverse-electric and transverse-magnetic polarizations. Rigorous couple-wave analysis and simulated annealing algorithm are employed to get the optimal parameters of the grating and accelerate the computing process. For the purpose of understanding the phenomenon of the beam incident, the finite element method is also applied to get the simulation result. It is proven that the proposed beam splitters all present great efficiency and uniformity on the energy distribution. High manufacturing tolerance of the beam splitters is also analyzed, which allows for greater flexibility in the fabrication process. Compared with beam splitters based on single-groove grating, multi-port beam splitters based on double grooves show great performance and universality.

Graphical abstract

中文翻译：

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用于太赫兹多功能分束器的双脊阵列超表面

摘要

与许多基于对称结构光栅的分束器的研究不同，本文提出了一种双槽结构的非对称光栅。基于双槽光栅，设计了在太赫兹频率下工作的正入射、横电偏振和横磁偏振的多端口分束器，包括双端口、三端口和四端口。采用严格的耦合波分析和模拟退火算法来获得光栅的最佳参数并加速计算过程。为了了解光束入射现象，还应用有限元方法得到模拟结果。事实证明，所提出的分束器都具有很高的效率和能量分布的均匀性。还分析了分束器的高制造公差，这使得制造过程具有更大的灵活性。与基于单槽光栅的分光器相比，基于双槽光栅的多端口分光器表现出良好的性能和通用性。

图形概要