Teng Yan, Xiao Yuhua, Xie Guoao, Li Chun, Wang Tengyu, Zhu Yifan, Huang Zhengwei, Liang Lanju, Yao Haiyun, Ren Yuan, Jiang Ling
Opt Express. 2025 Feb 24;33(4):7901-7913. doi: 10.1364/OE.542143.
In terahertz (THz) optical systems, beam splitters are essential components. However, they still have challenges in multi-channel manipulation of THz waves. Multi-channel beam splitters are devices that simultaneously split and independently control beams through multiple channels. In this paper, multi-channel polarization conversion beam splitters are designed to achieve independent modulation of four beams. The polarization control of the beam is achieved by integrating broadband polarization conversion cells with the form of a split ring resonance (SRR). The polarization conversion rate (PCR) exceeds 90% with broadband advantages. Four independently modulated beams are generated by combining sub-metasurfaces with gradient phases. The gradient phase consisting of 2-bit cells with a phase difference of 90° enables the beam to be deflected in any direction. Furthermore, the effect of polarization conversion for far-field beams is demonstrated in simulations. Finally, four structures are fabricated and measured, and the results are in agreement with the simulations at 0.23 THz or 0.85 THz. The proposed method provides an efficient way to control THz polarization conversion beam splitters in an independent approach.
在太赫兹（THz）光学系统中，分束器是必不可少的组件。然而，它们在太赫兹波的多通道操控方面仍面临挑战。多通道分束器是能够同时通过多个通道对光束进行分束和独立控制的器件。本文设计了多通道偏振转换分束器以实现对四束光的独立调制。通过将宽带偏振转换单元集成到裂环谐振（SRR）形式中实现光束的偏振控制。偏振转换率（PCR）超过90%且具有宽带优势。通过将亚表面与梯度相位相结合产生四束独立调制的光束。由相位差为90°的2位单元组成的梯度相位可使光束在任何方向上偏转。此外，在模拟中展示了远场光束的偏振转换效果。最后，制作并测量了四种结构，结果与在0.23太赫兹或0.85太赫兹下的模拟结果一致。所提出的方法为以独立方式控制太赫兹偏振转换分束器提供了一种有效途径。
