Abstract
Recently, there has been a surge of interest in square-root higher-order topological insulators (HOTIs) due to their unique topological properties inherited from their squared Hamiltonian. Different from conventional HOTIs, square-root HOTIs support paired corner states that exist in different bandgaps. In this work, we experimentally establish a series of two-dimensional photonic decorated Su–Schrieffer–Heeger (SSH) lattices by using the femtosecond-laser writing technique and thereby directly observe paired topological corner states. Interestingly, the higher-order topological properties of such square-root HOTIs are inherited from the parent Hamiltonian, which contains the celebrated 2D SSH lattice. The dynamic evolution of square-root corner states indicates that they exist in different bandgaps. This work not only provides a new platform to study higher-order topology in optics, it also brings about new possibilities for future studies of other novel HOTIs.
Original language | English |
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Pages (from-to) | 3765-3768 |
Number of pages | 4 |
Journal | Optics Letters |
Volume | 48 |
Issue number | 14 |
DOIs | |
State | Published - 15 Jul 2023 |
Bibliographical note
Publisher Copyright:© 2023 Optica Publishing Group.
Funding
Funding. Natural Science Foundation of Shandong Province (ZR2021 ZD02, ZR2023QA125); National Natural Science Foundation of China (12174222).
Funders | Funder number |
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National Natural Science Foundation of China | 12174222 |
Natural Science Foundation of Shandong Province | ZR2021 ZD02, ZR2023QA125 |