Schneider Tobias, Gao Wenlong, Zentgraf Thomas, Schumacher Stefan, Ma Xuekai
Department of Physics and Center for Optoelectronics and Photonics Paderborn (CeOPP), Paderborn University, 33098 Paderborn, Germany.
Eastern Institute for Advanced Study, Eastern Institute of Technology , Ningbo, Zhejiang , 315200, China.
Nanophotonics. 2024 Feb 2;13(4):509-518. doi: 10.1515/nanoph-2023-0556. eCollection 2024 Feb.
Topological states have been widely investigated in different types of systems and lattices. In the present work, we report on topological edge states in double-wave (DW) chains, which can be described by a generalized Aubry-André-Harper (AAH) model. For the specific system of a driven-dissipative exciton polariton system we show that in such potential chains, different types of edge states can form. For resonant optical excitation, we further find that the optical nonlinearity leads to a multistability of different edge states. This includes topologically protected edge states evolved directly from individual linear eigenstates as well as additional edge states that originate from nonlinearity-induced localization of bulk states. Extending the system into two dimensions (2D) by stacking horizontal DW chains in the vertical direction, we also create 2D multi-wave lattices. In such 2D lattices multiple Su-Schrieffer-Heeger (SSH) chains appear along the vertical direction. The combination of DW chains in the horizonal and SSH chains in the vertical direction then results in the formation of higher-order topological insulator corner states. Multistable corner states emerge in the nonlinear regime.
拓扑态已在不同类型的系统和晶格中得到广泛研究。在本工作中，我们报道了双波（DW）链中的拓扑边缘态，其可由广义奥布里 - 安德烈 - 哈珀（AAH）模型描述。对于受驱动 - 耗散激子极化子系统的特定体系，我们表明在这类势链中可形成不同类型的边缘态。对于共振光激发，我们进一步发现光学非线性导致不同边缘态的多重稳定性。这包括直接从单个线性本征态演化而来的拓扑保护边缘态以及源自体态非线性诱导局域化的额外边缘态。通过在垂直方向堆叠水平DW链将系统扩展到二维（2D），我们还创建了二维多波晶格。在这种二维晶格中，沿垂直方向出现多个苏 - 施里弗 - 黑格（SSH）链。水平方向的DW链与垂直方向的SSH链相结合，进而导致高阶拓扑绝缘体角态的形成。多重稳定角态出现在非线性区域。
