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Observation of Coherent Perfect Acoustic Absorption at an Exceptional Point
Yi-Fei Xia1, Zi-Xiang Xu1, Yu-Ting Yan1
1Nanjing University, Collaborative Innovation Center of Advanced Microstructures and Key Laboratory of Modern Acoustics, MOE, Institute of Acoustics, Department of Physics, Nanjing 210093, People's Republic of China.
Physical Review Letters
|August 27, 2025
Summary
Researchers achieved coherent perfect absorption (CPA) at an exceptional point (EP) in acoustics for the first time. This breakthrough utilizes non-Hermitian systems with imbalanced losses in a two-channel waveguide, enabling full wave absorption.
Area of Science:
- Acoustics
- Wave Physics
- Non-Hermitian Systems
Background:
- Non-Hermitian systems offer novel ways to control wave scattering using loss.
- Coherent Perfect Absorption at an Exceptional Point (CPA EP) has been a theoretical concept but remained unachieved in acoustics.
- Exploiting loss in wave phenomena is crucial for advanced device functionalities.
Purpose of the Study:
- To experimentally demonstrate Coherent Perfect Absorption at an Exceptional Point (CPA EP) in acoustic systems.
- To investigate the manipulation of wave scattering using engineered loss in non-Hermitian acoustics.
- To explore the potential of acoustic singularities for novel device applications.
Main Methods:
- Utilized a two-channel waveguide system incorporating compact lossy resonators.
- Implemented active components to independently modulate losses, creating imbalanced non-Hermiticity.
- Experimentally verified CPA EP by measuring full absorption at a specific real frequency.
Main Results:
- Successfully demonstrated CPA EP in an acoustic system for the first time.
- Observed full wave absorption at a unique real frequency, characteristic of CPA EP.
- Showcased high sensitivity of the CPA EP to variations in incident acoustic phase.
Conclusions:
- The experimental realization of CPA EP in acoustics opens new avenues for non-Hermitian physics in classical wave systems.
- Findings pave the way for developing innovative acoustic devices based on singularity phenomena.
- The demonstrated method provides a platform for exploring advanced control of acoustic waves.
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