What is it about?

We have proposed the two-dimensional inner and outer nested square lattice photonic crystals (2D IONSL PCs). The topological band inversions were achieved by changing the size of scatterers within the unit cell of the 2D IONSL PCs. Moreover, we have found the pair-partitioned bulk localized states (BLSs) in the box-shaped cavity constructed with topological non-trivial state PC surrounded by topological trivial state PC, and revealed that the optical field reflection and confinement mechanism induced by topological band inversions lead to the formation of the pair-partitioned BLSs.

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Why is it important?

Multi-mode vertical-cavity surface-emitting lasers (VCSELs) play an important role in short-reach links and high-performance computing applications owing to their low cost, low modal noise, and low power consumption. However, defects, impurities and perturbations introduced during the process of preparation can affect their performance. In addition, the design of cavity is also crucial. Therefore, multi-mode cavities of the topological PCs with robustness are to be investigated urgently. Furthermore, in order to enrich the PCs structure and provide a new platform for the research of topological physics, new PCs also need to be proposed.


The 2D IONSL PCs will provide a new platform for the research of topological physics, and the pair-partitioned BLSs will provide a new idea for the research of multi-mode cavities of the topological PCs, which are expected to be applied to topological VCSELs.

Jianjun Liu
Hunan University

Read the Original

This page is a summary of: Pair-partitioned bulk localized states induced by topological band inversion, Applied Physics Letters, July 2022, American Institute of Physics,
DOI: 10.1063/5.0101925.
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