Novel phononic-crystal-arrayed acoustic metalens for long beam focusing in multi-band

Abstract

We propose a multi-band acoustic metalen that achieves 18-26λ long-range beam focusing and narrow full width at half maximum (FWHM) of 4-5λ across multiple frequency bands, utilizing principles of multiple scattering theory. The metalens sample was meticulously fabricated using quadrilateral lattice scatterers in the cross-section, and its experimental acoustic field tests showed focused sound beams with a length of 0.78 - 1.07 m falling within the frequency bands of 5800 - 6100 Hz, 8500 - 8700 Hz, and 9700 - 9900 Hz. This study holds potential applications in acoustic directional projection, signal enhancement, and acoustic power collection.