Observation of Ultra‐High‐Q Resonators in the Ultrasound via Bound States in the Continuum

• DOI: 10.1002/advs.202402917
• Publication Date: 2024-07-04T09:37:33Z
• Authors: Mohamed Farhat; Younes Achaoui; Julio Andrés Igle...; Mahmoud Addouche; Ying Wu; Abdelkrim Khelif
• Keywords: bound states in the continuum; Subwavelength Imaging; Acoustic Metamaterials; Resonator; Science; Biomedical Engineering; Bound state; High frequency ultrasound; FOS: Physical sciences; Physics - Classical Physics; Applied Physics (physics.app-ph); FOS: Medical engineering; Quantum mechanics; Engineering; Fabry–Perot resonators; Ultrasound; high quality factors; Optoelectronics; Guided Wave Structural Health Monitoring in Materials; Nonlinear Ultrasonic Techniques; Acoustic Metamaterials and Phononic Crystals; High-Resolution Seismic Noise Tomography; ultrasound; Physics; Q; Classical Physics (physics.class-ph); Physics - Applied Physics; FOS: Earth and related environmental sciences; Acoustics; metasurfaces; Materials science; Earth and Planetary Sciences; underwater acoustics; Geophysics; Mechanics of Materials; Physical Sciences; Local Resonances; Research Article; Ultrasonic Arrays

AbstractThe confinement of waves in open systems represents a fundamental phenomenon extensively explored across various branches of wave physics. Recently, significant attention is directed toward bound states in the continuum (BIC), a class of modes that are trapped but do not decay in an otherwise unbounded continuum. Here, the theoretical investigation and experimental demonstration of the existence of quasi‐bound states in the continuum (QBIC) for ultrasonic waves are achieved by leveraging an elastic Fabry–Pérot metasurface resonator. Several intriguing properties of the ultrasound quasi‐bound states in the continuum that are robust to parameter scanning are unveiled, and experimental evidence of a remarkable Q‐factor of 350 at ≈1 MHz frequency, far exceeding the state‐of‐the‐art using a fully acoustic underwater system is presented. The findings contribute novel insights into the understanding of BIC for acoustic waves, offering a new paradigm for the design of efficient, ultra‐high Q‐factor ultrasound devices.