Acoustic enhancement and weak signal detection based on quasibound states in the continuum

Acoustic signal detection is important in several fields of research. However, realizing weaksignal detection remains a challenge. Recently, the bound state in continuum (BIC) has attracted considerable attention because of its ultrahigh quality-factor (Q-factor) and strong field enhancement. In this study, we achieved two Fabry-Perot BICs (bonding and anti-bonding BICs) in a coupled-resonator system and a mirror-induced BIC in a single-resonator system. And the acoustic enhancement from quasi-BICs of the coupled-resonator system and single-resonator system was investigated in the simulation. Compared to the coupled-resonator system, the amplification performance of the single-resonator system was better and verified in the experiment. The experimental results agreed with the numerical results, and the maximum pressure magnification was approximately 28x. Furthermore, the single-resonator system enhanced the weak harmonic signal, weak periodic impulse signal, and weak modulated signal in the presence of strong background noise, making signal detection much easier. We believe that this work provides a new method to realize weak signal detection based on acoustic enhancement.