We propose a pseudospin-field-dependent waveguide (PFDW) by constructing a sandwiched heterostructure consisting of three magneto-optical photonic crystals (MOPCs) with different geometric parameters. The upper expanded MOPC applied with an external magnetic field has broken time-reversal symmetry (TRS) and an analogous quantum spin Hall (QSH) effect, while the middle standard and the lower compressed ones are not magnetized and trivial. Attributed to the TRS-broken-QSH effect of the upper MOPC, the topological large-area one-way transmission that uniformly distributes over the middle domain is achieved and exhibits the characteristics of a pseudospin-field-momentum-locking; i.e., pseudospin-down (or pseudospin-up) leftward (or rightward) waveguide state when the positive (or negative) magnetic field is applied on the upper MOPC. We further demonstrate the strong robustness of the PFDW against backscattering from various kinds of defects. In addition, a topological beam modulator that can compress or expand the light beam, and a large-area pseudospin beam splitter have been designed. These results have potential in various applications such as sensing, signal processing, and optical communications.

中文翻译：

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使用磁光光子晶体的伪自旋场相关波导中的拓扑大面积单向传输

我们通过构建由三个具有不同几何参数的磁光光子晶体 (MOPC) 组成的夹层异质结构，提出了赝自旋场相关波导 (PFDW)。施加外部磁场的上部扩展 MOPC 打破了时间反转对称性 (TRS) 和类似的量子自旋霍尔 (QSH) 效应，而中间标准和下部压缩的未磁化且微不足道。由于上层 MOPC 的 TRS-broken-QSH 效应，实现了在中间域上均匀分布的拓扑大面积单向传输，并表现出赝自旋场动量锁定的特征；即，当在上部 MOPC 上施加正（或负）磁场时，伪自旋向下（或伪自旋向上）向左（或向右）波导状态。我们进一步证明了 PFDW 对来自各种缺陷的反向散射的强大鲁棒性。此外，还设计了可以压缩或扩展光束的拓扑光束调制器，以及大面积赝自旋分束器。这些结果在传感、信号处理和光通信等各种应用中具有潜力。