[论文解读] Reconfigurable Curved Beams at Terahertz Frequencies Using Inverse-Designed Bilayer Diffractive Structures

Wei Jia, Miguel Gomez+2 more|arXiv (Cornell University)|Feb 9, 2026

Orbital Angular Momentum in Optics被引用 0

一句话总结

作者展示使用两层反设计双层衍射光学元件的被动、可重构太赫兹曲线波束；通过将第二层旋转180°来改变轨迹，而不改变入射波或层设计，结果通过仿真与实验验证。

ABSTRACT

Curved electromagnetic beams at terahertz (THz) frequencies have recently emerged as a powerful example of wavefront engineering, with applications in imaging and high-capacity wireless communications. Unlike canonical self-accelerating solutions such as Airy beams, general curved-beam propagation enables arbitrary, application-specific trajectories that are not constrained by analytic beam families. Here, we demonstrate a passive and reconfigurable approach for generating trajectory-engineered THz curved beams using inverse-designed bilayer diffractive optical elements (DOEs). Two phase-only diffractive layers are optimized using gradient-based inverse design to produce predetermined curved propagation paths. Reconfiguration is achieved by a 180° rotation of the second layer, which modifies the effective phase profile of the cascaded structure without altering the incident wave or individual layer designs. The proposed system can produce distinct curved trajectories with controlled transverse displacement and beam confinement, as confirmed by scalar diffraction simulations and experimental measurements. Overall, this work establishes inverse-designed cascaded DOEs as a compact and scalable platform for reconfigurable trajectory control of THz beams, providing a flexible alternative to analytic self-accelerating beams for radiative near-field THz communications.

研究动机与目标

• 推动轨迹工程化的THz 波束用于成像与高容量无线应用。
• 开发一种被动、可重构的波束整形平台，使用反设计的双层DOE。
• 在不改变入射波或单层设计的情况下，实现不同的曲线传播路径。

提出的方法

• 通过梯度反设计对两个仅相位衍射层进行优化，以产生预定的曲线轨迹。
• 级联两个双层DOE以定制整体相位轮廓和波束路径。
• 通过对第二层旋转180°实现重配置，在不改变入射波或层设计的情况下调制级联相位。
• 用标量衍射仿真验证设计，并进行实验测量以确认轨迹控制。

实验结果

研究问题

• RQ1 级联的一对反设计双层DOE能否产生可控的太赫兹曲线波束轨迹？
• RQ2 将一层旋转180°如何影响有效相位轮廓和结果波束路径？
• RQ3 标量衍射仿真是否与可重构THz波束的实验测量一致？

主要发现

• 级联的双层DOE系统可以产生不同的曲线THz轨迹。
• 通过对第二层旋转180°实现重配置，从而改变有效相位轮廓。
• 结果通过标量衍射仿真和实验测量得到证实。
• 该方法为THz波束的可重构轨迹控制提供了紧凑且可扩展的平台。
• 该方法为辐射近场THz通信提供了相对于解析自加速波的灵活替代方案。