Compact asymmetric sound absorber at the exceptional point

We present an asymmetric absorber at an exceptional point (EP) with a compact configuration and deep-subwavelength thickness. Unlike conventional side-branched sound absorbers in dual-port systems, the proposed asymmetric absorber exhibits a compact shape that is coaxial with the waveguide. By tunin...

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Bibliographic Details
Published in:Science China. Physics, mechanics & astronomy mechanics & astronomy, 2021-04, Vol.64 (4), p.244303, Article 244303
Main Authors: Li, DongTing, Huang, SiBo, Cheng, Yi, Li, Yong
Format: Article
Language:English
Subjects:
Absorbers
Absorption
Acoustic absorption
Acoustics
Astronomy
Asymmetry
Classical and Continuum Physics
Observations and Techniques
Photonics
Physics
Physics and Astronomy
Sound transmission
Ventilation
Waveguides
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Summary:We present an asymmetric absorber at an exceptional point (EP) with a compact configuration and deep-subwavelength thickness. Unlike conventional side-branched sound absorbers in dual-port systems, the proposed asymmetric absorber exhibits a compact shape that is coaxial with the waveguide. By tuning the loss and geometric parameters of the non-Hermitian system to reach an EP, we observe extreme asymmetric absorption. This phenomenon is theoretically and experimentally validated by observing a quasi-perfect absorption and a near-total reflection for opposite incidences at the ultra-thin (1/28th of the operating wavelength) neck-embedded tube employed in this study. Furthermore, we demonstrate an EP-induced tunable asymmetric absorption. Our study proposes novel approaches to manipulate the EP-induced wave phenomena, paving the way for the development of novel acoustic absorbers, sensors, isolators, and directional devices.
ISSN:1674-7348
1869-1927
DOI:10.1007/s11433-020-1612-1