Higher‐Order States in a Non‐Hermitian 3D Topological Photonic Crystal

作者：Xiaoxiao Wang, Ruizhe Gu, Yandong Li, Huixin Qi, Xiaoyong Hu, Qihuang Gong · 发表于：Laser & Photonics Review · 年份：2023 · DOI：10.1002/lpor.202300204 · 被引用次数：9 · 研究领域：Topological Materials and Phenomena、Quantum Mechanics and Non-Hermitian Physics、Photorefractive and Nonlinear Optics

Abstract Higher‐order topological insulators hosting topological modes at hinges and corners provide a new avenue for disorder‐immune light transport, which prospects great potential in applications of integrated photonics devices. However, the active control of topological modes in 3D higher‐order topological insulators is not realized yet, and its construction is too complicated and huge to analyze. Here, a method is proposed to construct effective Hamiltonians for higher‐order topological insulators, which provides a correct physical picture of the states and the corresponding energies at the domain walls. A non‐Hermitian 3D honeycomb lattice is constructed, which can generate arbitrary‐located, arbitrary‐shaped, and robust topological hinge states propagating at gain‐loss domain walls. The 3D honeycomb lattice can also appear as non‐Hermitian third‐order TIs exhibiting corner states, which can be dynamically controlled and show new topologically protected confinement rules. This work expands the understanding of the topological properties in non‐Hermitian systems and enables the dynamic control of topological states of different dimensions.