讲座主题

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 seminar, 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.