The study of one-way edge states of electromagnetic wave based on quantum Hall effect in photonic crystals (PCs) has recently made a great progress. In particular, the pseudo-spin states in topological PCs made of dielectric materials can be realized by breaking pseudo-time-reversal symmetry. We perform a research on the influence of parameters, such as lattice constant, dielectric permittivity of cylinders, radius of the dielectric cylinder and scaling factor of PCs, on the photonic bandgaps of topological PCs. Based on the analysis results, we present a 2D topological PC configuration that supports robust unidirectional helical edge states along zigzag interface between the topologically trivial and nontrivial PCs. With the structure, an operating bandwidth as larger as of \(0.0173\;(2\pi c/a)\), robust helical edge states with energy-condensed and great nonreciprocity can be achieved by exciting a circularly polarized source. Utilizing this kind of architecture, we construct Z-shaped channel to demonstrate the robustness of helical edge states transport in different cases. The research offers a valid way for realizing unidirectional edge states with robust transport in practicable quantum communication applications.

中文翻译：

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全介电拓扑光子晶体的单向螺旋边缘态

基于量子霍尔效应的光子晶体（PCs）电磁波单向边缘状态的研究近来取得了很大的进展。尤其是，由电介质材料制成的拓扑PC中的伪自旋状态可以通过打破伪时间反转对称性来实现。我们对晶格常数，圆柱体的介电常数，圆柱体的半径和PC的缩放因子等参数对拓扑PC的光子带隙的影响进行了研究。基于分析结果，我们提出了一种2D拓扑PC配置，该配置支持沿拓扑琐碎的PC和非琐碎的PC之间的锯齿形界面的鲁棒单向螺旋边缘状态。通过这种结构，工作带宽大于\（0.0173 \;（2 \ pi c / a）\）通过激发圆极化光源，可以实现具有能量压缩和强大的不可逆性的强大的螺旋边缘状态。利用这种架构，我们构造了Z形通道，以证明在不同情况下螺旋边缘状态传输的鲁棒性。该研究为在可行的量子通信应用中通过鲁棒传输实现单向边缘状态提供了有效的方法。