太赫兹伪表面等离子体波导阵列对Floquet拓扑模式的实现

Realization of Floquet Topological Modes via Terahertz Pseudo-Surface Plasmonic Waveguide Arrays

摘要: 拓扑光子学已经拓展到了周期性调制了Floquet体系，这种体系由于受到周期性调制而展示出新颖的特性，例如，全新的拓扑模式反常π模的发现，这种模式表现出与静态拓扑体系中的边界态完全不同的特性。这里，我们在太赫兹频段上基于伪表面等离子体波导阵列模拟了周期性驱动的SSH模型，并通过太赫兹近场系统观察到了Floquet拓扑模式，沿着阵列的边界传播。为了验证异常边缘模式的存在性，我们通过Floquet理论明确计算了系统准能量的拓扑不变量以确定其相图。我们的工作为在太赫兹波段研究波导阵列中的拓扑模式提供了新的途径。

Abstract: Recent advances in topological photonics have extended to periodically modulated Floquet systems, which exhibit novel characteristics due to temporal periodicity, such as the discovery of anomalous π-modes that demonstrate fundamentally different properties compared to boundary states in static topological systems. Here, we numerically simulate a periodically driven Su-Schrieffer-Heeger (SSH) model using terahertz pseudo-surface plasmonic waveguide arrays and experimentally observe Floquet topological modes propagating along array boundaries through terahertz near-field measurements. To verify the existence of these anomalous edge modes, we rigorously calculate the system’s topological invariants in quasi-energy space via Floquet theory to establish its phase diagram. This work paves a new avenue for investigating topological modes in waveguide arrays within the terahertz regime.