Topology‐Optimized Bound States in the Continuum with High‐Q Acoustic Field Enhancement

Abstract Achieving high‐quality (high‐Q) acoustic resonances remains a critical goal in acoustic device design, given their exceptional sound manipulation capabilities. However, enhancing Q‐factors is often hindered by energy dissipation and material losses, except for leveraging bound states in the continuum (BICs). This paper introduces a methodology utilizing topology optimization to achieve high‐Q resonances based on the concept of BICs, which effectively confine acoustic waves by minimizing energy leakage. This method explores entirely new topology classes through the optimization of a single unit cell embedded within periodic arrays. By engineering quasi‐BIC modes and experimentally validating sharp pressure field enhancements, a robust technique that enables precise tuning of resonance frequencies and improves resilience against external perturbations, which is challenging for the conventional parameter‐tuning approach is presented. These findings show promise for advancing wave‐confining applications, such as energy harvesting and acoustic filtering, while pushing the performance boundaries of acoustic devices.