Higher-order topological states in photonic kagome crystals with long-range interactions

Mengyao Li, Dmitry Zhirihin, Maxim Gorlach, Xiang Ni, Dmitry Filonov, Alexey Slobozhanyuk, Andrea Alù, Alexander B. Khanikaev*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Photonic topological insulators enable topological boundary modes that are resilient to defects and disorder, irrespective of manufacturing precision. This property is known as topological protection. Although originally limited to dimensionality of modes one lower than that of topological insulators, the recently discovered higher-order topological insulators (HOTIs) offer topological protection over an extended range of dimensionalities. Here, we introduce a photonic HOTI with kagome lattice that exhibits topological bulk polarization, leading to the emergence of one-dimensional edge states, as well as higher-order zero-dimensional states confined to the corners of the structure. Interestingly, in addition to the corner states due to nearest-neighbour interactions, we discover a new class of topological corner states induced by long-range interactions and specific to photonic systems. Our findings demonstrate that photonic HOTIs possess richer physics than their condensed-matter counterparts, offering opportunities for engineering novel designer electromagnetic states with unique topological robustness.

Original languageEnglish
Pages (from-to)89-94
Number of pages6
JournalNature Photonics
Volume14
Issue number2
DOIs
StatePublished - 1 Feb 2020
Externally publishedYes

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