Acoustic Bound States in the Continuum in Coupled Helmholtz Resonators

Abstract

Resonant states underlie a variety of metastructures that exhibit remarkable capabilities for effective control of acoustic waves at subwavelength scales. The development of metamaterials relies on the rigorous mode engineering providing the implementation of the desired properties. At the same time, the application of metamaterials is still limited as their building blocks are frequently characterized by complicated geometry and can't be tuned easily. In this work, we consider a simple system of coupled Helmholtz resonators and study their properties associated with the tuning of coupling strength and symmetry breaking. We numerically and experimentally demonstrate the excitation of quasi-bound state in the continuum in the resonators placed in a free space and in a rectangular cavity. It is also shown that tuning the intrinsic losses via introducing porous inserts can lead to spectral splitting or merging of quasi-\textit{bound states in the continuum} and occurrence of \textit{exceptional points}. The obtained results will open new opportunities for the development of simple and easy-tunable metastructures based on Helmholtz resonances.

References in corpus (8)

• The physics of exceptional points
• Topological acoustics
• Applications of Bound States in the Continuum in Photonics
• Bound states in the continuum in photonic structures
• Stabilization of acoustic modes using Helmholtz and Quarter-Wave resonators tuned at exceptional points
• Metahouse: noise-insulating chamber based on periodic structures
• Microacoustic metagratings at ultra-high frequencies fabricated by two-photon lithography
• Exceptional points in single open acoustic resonator due to the symmetry breaking

Cited by in corpus (2)

• Lattice-induced sound trapping in biperiodic metasurfaces of acoustic resonators
• Acoustic scattering singularities via quasi-Bound states in the continuum