Elastic Metasurfaces: Unlocking the Potential of Bound States in the Continuum
B1 R4214
This talk will briefly introduce the main mechanisms that generate elastic elastic bound states in the continuum (BICs) and show how slight symmetry breaking converts them into quasi-BICs with controllable radiation leakage.
Overview
Elastic bound states in the continuum (BICs) are non-radiating vibrational modes embedded in the spectrum of propagating elastic waves, offering an extreme route to trap mechanical energy in open structures [1].
In this talk, I will briefly introduce the main mechanisms that generate elastic BICs and show how slight symmetry breaking converts them into quasi-BICs with controllable radiation leakage. This tunability makes BICs powerful building blocks for vibration control: by matching radiative and material losses, quasi-BICs can be driven to act as elastic absorbers that strongly absorb and localize vibration energy in compact regions, enabling lightweight vibration absorbers and isolation stages with effective high-Q performance [2]. I will then discuss how the same sharp, interference-driven features can be exploited for sensing, where localized strain fields and steep dispersive responses translate into enhanced sensitivity to added mass, or mechaniocal properties changes [3]. Finally, I will show how coupling BIC-based resonances in non-Hermitian architectures leads to exceptional points (EPs), where multiple eigenmodes and eigenvalues coalesce [4]. Operating near higher-order EPs built from quasi-BICs can, in principle, combine the large energy buildup of BICs with the eigenvalue hypersensitivity of EPs, offering new strategies for ultra-responsive vibration and strain sensors and for switchable vibration absorption states.
References
- L. Cao et al. "Elastic bound state in the continuum with perfect mode conversion". Journal of the Mechanics and Physics of Solids 154 (2021) 104502.
- L. Cao et al. "Perfect absorption of flexural waves induced by bound state in the continuum". Extreme Mechanics Letters 47 (2021) 101364.
- S. An, T. Liu, L. Cao, Z. Gu, H. Fan, Y. Zeng, L. Cheng, J. Zhu & M. B. Assouar. "Multibranch Elastic Bound States in the Continuum". Phys. Rev. Lett. 132 (2024) 187202.
- L. Cao & M. B. Assouar. "Asymmetric Elastic Bound State in the Continuum by Exceptional Point". Phys. Rev. Lett. 135 (2025) 246301.
Presenters
Badreddine Assouar, Professor, Director of Research at French National Center of Scientific Research (CNRS), University of Lorraine (UL), France
Brief Biography
Badreddine Assouar is a Research Director at CNRS and the University of Lorraine. He received his PhD in Materials Physics from Nancy University (France) in 2001. In 2002, he became a Research Scientist at CNRS. He obtained his habilitation to supervise research (HDR) in 2007 and became a Research Professor. In 2010, he joined the Georgia Institute of Technology in Atlanta as a Visiting Professor. Since 2013, he has founded and led the Acoustic Metamaterials and Phononics group at the University of Lorraine, where he conducts research on acoustic and elastic metamaterials, metasurfaces, phononics, and wave physics.
Badreddine is a Fellow of American Physical Society and a Fellow of the European Academy of Sciences, and has been a valued member of the APS community as an Associate Editor for Physical Review Applied, and since 2025, he is the inaugural Chief Editor of APS Open Science.
