Flatbands from Bound States in the Continuum for Orbital Angular Momentum Localization

Fuente: arXiv
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Main Authors: Zhu, Weiwei, Zou, Hongyu, Ge, Yong, Wang, Yin, Cheng, Zheyu, Wang, Bing-bing, Yuan, Shou-qi, Sun, Hong-xiang, Xue, Haoran, Zhang, Baile
Format: Preprint
Published: 2024
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_version_ 1866909337035735040
author Zhu, Weiwei
Zou, Hongyu
Ge, Yong
Wang, Yin
Cheng, Zheyu
Wang, Bing-bing
Yuan, Shou-qi
Sun, Hong-xiang
Xue, Haoran
Zhang, Baile
author_facet Zhu, Weiwei
Zou, Hongyu
Ge, Yong
Wang, Yin
Cheng, Zheyu
Wang, Bing-bing
Yuan, Shou-qi
Sun, Hong-xiang
Xue, Haoran
Zhang, Baile
contents A flatband material is a system characterized by energy bands with zero dispersion, allowing for the compact localization of wavefunctions in real space. This compact localization significantly enhances inter-particle correlations and light-matter interactions, leading to notable advancements such as fractional Chern insulators in condensed matter systems and flat-band lasers in photonics. Previous flatband platforms, including twisted bilayer graphene and artificial kagome/Lieb lattices, typically focused on nondegenerate flatbands, lacking access to the high degeneracy that can facilitate the localization of orbital angular momentum (OAM). Here, we propose a general framework to construct highly degenerate flatbands from bound states in the continuum (BICs)--a concept originating from quantum theory but significantly developed in photonics and acoustics in recent years. The degeneracy of flatbands is determined by the number of BICs within each unit cell in a lattice. We experimentally validate this approach in two-dimensional (2D) and three-dimensional (3D) acoustic crystals, demonstrating flatbands with 4-fold and 12-fold degeneracies, respectively. The high degeneracy provides sufficient internal degrees of freedom, enabling the selective excitation of localized OAM at any position in any direction. Our results pave the way for exploring BIC-constructed flatbands and their localization properties.
format Preprint
id arxiv_https___arxiv_org_abs_2410_04040
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Flatbands from Bound States in the Continuum for Orbital Angular Momentum Localization
Zhu, Weiwei
Zou, Hongyu
Ge, Yong
Wang, Yin
Cheng, Zheyu
Wang, Bing-bing
Yuan, Shou-qi
Sun, Hong-xiang
Xue, Haoran
Zhang, Baile
Optics
Mesoscale and Nanoscale Physics
A flatband material is a system characterized by energy bands with zero dispersion, allowing for the compact localization of wavefunctions in real space. This compact localization significantly enhances inter-particle correlations and light-matter interactions, leading to notable advancements such as fractional Chern insulators in condensed matter systems and flat-band lasers in photonics. Previous flatband platforms, including twisted bilayer graphene and artificial kagome/Lieb lattices, typically focused on nondegenerate flatbands, lacking access to the high degeneracy that can facilitate the localization of orbital angular momentum (OAM). Here, we propose a general framework to construct highly degenerate flatbands from bound states in the continuum (BICs)--a concept originating from quantum theory but significantly developed in photonics and acoustics in recent years. The degeneracy of flatbands is determined by the number of BICs within each unit cell in a lattice. We experimentally validate this approach in two-dimensional (2D) and three-dimensional (3D) acoustic crystals, demonstrating flatbands with 4-fold and 12-fold degeneracies, respectively. The high degeneracy provides sufficient internal degrees of freedom, enabling the selective excitation of localized OAM at any position in any direction. Our results pave the way for exploring BIC-constructed flatbands and their localization properties.
title Flatbands from Bound States in the Continuum for Orbital Angular Momentum Localization
topic Optics
Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2410.04040