Nonlinear photonic disclination states

Higher-order topological insulators are unusual materials that can support topologically protected states, whose dimensionality is lower than the dimensionality of the structure at least by 2. Among the most intriguing examples of such states are zero-dimensional corner modes existing in two-dimensi...

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Main Authors: Boquan Ren, Hongguang Wang, Yaroslav V. Kartashov, Yongdong Li, Yiqi Zhang
Format: Article
Language:English
Published: AIP Publishing LLC 2023-01-01
Series:APL Photonics
Online Access:http://dx.doi.org/10.1063/5.0126104
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author Boquan Ren
Hongguang Wang
Yaroslav V. Kartashov
Yongdong Li
Yiqi Zhang
author_facet Boquan Ren
Hongguang Wang
Yaroslav V. Kartashov
Yongdong Li
Yiqi Zhang
author_sort Boquan Ren
collection DOAJ
description Higher-order topological insulators are unusual materials that can support topologically protected states, whose dimensionality is lower than the dimensionality of the structure at least by 2. Among the most intriguing examples of such states are zero-dimensional corner modes existing in two-dimensional higher-order insulators. In contrast to corner states, recently discovered disclination states also belong to the class of higher-order topological states but are bound to the boundary of the disclination defect of the higher-order topological insulator and can be predicted using the bulk-disclination correspondence principle. Here, we present the first example of the nonlinear photonic disclination state bifurcating from its linear counterpart in the disclination lattice with a pentagonal or heptagonal core. We show that nonlinearity allows us to tune the location of the disclination states in the bandgap and notably affects their shapes. The structure of the disclination lattice is crucial for the stability of these nonlinear topological states: for example, disclination states are stable in the heptagonal lattice and are unstable nearly in the entire gap of the pentagonal lattice. Nonlinear disclination states reported here are thresholdless and can be excited even at low powers. Nonlinear zero-energy states coexisting in these structures with disclination states are also studied. Our results suggest that disclination lattices can be used in the design of various nonlinear topological functional devices, while disclination states supported by them may play an important role in applications, where strong field confinement together with topological protection are important, such as the design of topological lasers and enhancement of generation of high harmonics.
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spelling doaj.art-cd7b54f7f39441b2958f0b66567c4e342023-02-03T16:25:45ZengAIP Publishing LLCAPL Photonics2378-09672023-01-0181016101016101-1010.1063/5.0126104Nonlinear photonic disclination statesBoquan Ren0Hongguang Wang1Yaroslav V. Kartashov2Yongdong Li3Yiqi Zhang4Key Laboratory for Physical Electronics and Devices of the Ministry of Education & Shaanxi Key Lab of Information Photonic Technique, School of Electronic Science and Engineering, Faculty of Electronic and Information Engineering, Xi’an Jiaotong University, Xi’an 710049, ChinaKey Laboratory for Physical Electronics and Devices of the Ministry of Education & Shaanxi Key Lab of Information Photonic Technique, School of Electronic Science and Engineering, Faculty of Electronic and Information Engineering, Xi’an Jiaotong University, Xi’an 710049, ChinaInstitute of Spectroscopy, Russian Academy of Sciences, Troitsk, Moscow 108840, RussiaKey Laboratory for Physical Electronics and Devices of the Ministry of Education & Shaanxi Key Lab of Information Photonic Technique, School of Electronic Science and Engineering, Faculty of Electronic and Information Engineering, Xi’an Jiaotong University, Xi’an 710049, ChinaKey Laboratory for Physical Electronics and Devices of the Ministry of Education & Shaanxi Key Lab of Information Photonic Technique, School of Electronic Science and Engineering, Faculty of Electronic and Information Engineering, Xi’an Jiaotong University, Xi’an 710049, ChinaHigher-order topological insulators are unusual materials that can support topologically protected states, whose dimensionality is lower than the dimensionality of the structure at least by 2. Among the most intriguing examples of such states are zero-dimensional corner modes existing in two-dimensional higher-order insulators. In contrast to corner states, recently discovered disclination states also belong to the class of higher-order topological states but are bound to the boundary of the disclination defect of the higher-order topological insulator and can be predicted using the bulk-disclination correspondence principle. Here, we present the first example of the nonlinear photonic disclination state bifurcating from its linear counterpart in the disclination lattice with a pentagonal or heptagonal core. We show that nonlinearity allows us to tune the location of the disclination states in the bandgap and notably affects their shapes. The structure of the disclination lattice is crucial for the stability of these nonlinear topological states: for example, disclination states are stable in the heptagonal lattice and are unstable nearly in the entire gap of the pentagonal lattice. Nonlinear disclination states reported here are thresholdless and can be excited even at low powers. Nonlinear zero-energy states coexisting in these structures with disclination states are also studied. Our results suggest that disclination lattices can be used in the design of various nonlinear topological functional devices, while disclination states supported by them may play an important role in applications, where strong field confinement together with topological protection are important, such as the design of topological lasers and enhancement of generation of high harmonics.http://dx.doi.org/10.1063/5.0126104
spellingShingle Boquan Ren
Hongguang Wang
Yaroslav V. Kartashov
Yongdong Li
Yiqi Zhang
Nonlinear photonic disclination states
APL Photonics
title Nonlinear photonic disclination states
title_full Nonlinear photonic disclination states
title_fullStr Nonlinear photonic disclination states
title_full_unstemmed Nonlinear photonic disclination states
title_short Nonlinear photonic disclination states
title_sort nonlinear photonic disclination states
url http://dx.doi.org/10.1063/5.0126104
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AT yiqizhang nonlinearphotonicdisclinationstates