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arXiv 2212.04042physics.opticsnlin.PS
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非线性光子向错态

Nonlinear photonic disclination states

Boquan Ren, Hongguang Wang, Yaroslav V. Kartashov, Yongdong Li, Yiqi Zhang

摘要:

高阶拓扑绝缘体是可以支持拓扑保护态的不寻常材料,其维数至少比结构的维数低2。这种状态最有趣的例子是存在于二维高阶绝缘体中的零维角模。与角态不同,最近发现的向错态也属于高阶拓扑态,但被束缚在高阶拓扑绝缘体的向错缺陷的边界上,并且可以使用体向错对应原理来预测。在这里,我们提出了第一个例子的非线性光子向错态分叉从它的线性对应的向错晶格的五边形或七边形的核心。我们表明,非线性允许调整位置的带隙中的向错状态,并显着影响其形状。向错晶格的结构对这些非线性拓扑状态的稳定性至关重要:例如,向错态在七角晶格中是稳定的,而在五角晶格的几乎整个间隙中是不稳定的。这里报道的非线性向错态是无阈值的,即使在低功率下也可以被激发。同时还研究了非线性零能态与向错态共存的情况。我们的研究结果表明,向错晶格可用于各种非线性拓扑功能器件的设计,而由它们支持的向错态可能在应用中发挥重要作用,其中强场限制和拓扑保护是重要的,如拓扑激光器的设计和增强产生高次谐波。

英文摘要:

Higher-order topological insulators are unusual materials that can support topologically protected states, whose dimensionality is lower than the dimensionality of the structure at least by 2. Among the most intriguing examples of such states are zero-dimensional corner modes existing in two-dimensional higher-order insulators. In contrast to corner states, recently discovered disclination states also belong to the class of higher-order topological states, but are bound to the boundary of the disclination defect of the higher-order topological insulator and can be predicted using the bulk-disclination correspondence principle. Here, we present the first example of the nonlinear photonic disclination state bifurcating from its linear counterpart in the disclination lattice with a pentagonal or heptagonal core. We show that nonlinearity allows to tune location of the disclination states in the bandgap and notably affects their shapes. The structure of the disclination lattice is crucial for stability of these nonlinear topological states: for example, disclination states are stable in the heptagonal lattice and are unstable nearly in the entire gap of the pentagonal lattice. Nonlinear disclination states reported here are thresholdless and can be excited even at low powers. Nonlinear zero-energy states coexisting in these structures with disclination states are also studied. Our results suggest that disclination lattices can be used in the design of various nonlinear topological functional devices, while disclination states supported by them may play an important role in applications, where strong field confinement together with topological protection are important, such as the design of topological lasers and enhancement of generation of high harmonics.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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