Merging bound states in the continuum in an open acoustic resonator  

作　　者：Lujun Huang Bin Jia Artem S.Pilipchuk Sibo Huang Chen Shen Almas F.Sadreev Yong Li Andrey E.Miroshnichenko 

机构地区：[1]School of Physics and Electronic Sciences,East China Normal University,Shanghai 200241,China [2]Institute of Acoustics,Tongji University,Shanghai 200092,China [3]L.V.Kirensky Institute of Physics,Krasnoyarsk 660036,Russia [4]Department of Mechanical Engineering,Rowan University,Glassboro 08028,USA [5]School of Engineering and Technology,University of New South Wales at Canberra,ACT 2610,Australia

出　　处：《Science China(Physics,Mechanics & Astronomy)》2025年第1期120-127,共8页中国科学:物理学、力学、天文学(英文版)

基　　金：supported by the National Natural Science Foundation of China(Grant No.12074286);Shanghai Science and Technology Committee(Grant No.21JC1405600);supported by the Australian Research Council Discovery Project(Grant No.DP200101353);supported by Russian Science Foundation(Grant No.22-12-00070)。

摘　　要：Bound states in the continuum(BICs)are perfectly localized resonances despite embedding in the continuum spectrum.However,an isolated BIC is very sensitive to the structure perturbation.Here,we report merging acoustic BICs in a single open resonator,robust against the structure perturbation.We find that both symmetry-protected BIC and Friedrich-Wintgen BIC are sustained in a single coupled waveguide-resonator system.By varying the height and length of the resonator,these two BICs move toward each other and merge into a single one at a critical dimension.Compared to an individual BIC,the merged BIC is robust against fabrication error because its Q-factor is proportional toΔL^(−4),whereΔL embodies the structure perturbation.The essence of this extraordinary phenomenon is perfectly explained by the two-and three-level approximations of the effective non-Hermitian Hamiltonian.Finally,we present direct experimental demonstrations of the moving and merging of BICs in a coupled 3D waveguide-resonator,which are evidenced by the vanishing of the linewidth of Fano resonance in the transmission spectra.Our results may find exciting applications in designing high-quality acoustic sources,sensors and filters.

关 键 词：acoustic resonances bound state in the continuum high-Q resonances 

分 类 号：O42[理学—声学]