Design and characterization of an acoustic composite lens with high-intensity and directionally controllable focusing

Acoustic orientation and bunching methods, which include the radiation surface expansion, ultrasonic demodulation, multiunit coherence, phased arrays and acoustic lenses, can be used to manipulate and focus sound waves. Recently, focusing systems composed of acoustic lenses have been found to offer high controllability and focusing intensity. In this paper, a newly designed composite acoustic lens that can achieve wave convergence is proposed by assembling a lattice array of concave hexagonal (CH)-shaped rods. In comparison with the latest published work, the new CH structure improves upon the focusing capability of traditional acoustic lenses while retaining their advantages in terms of 3-D underwater focusing. Simulated and experimental results show that a lens with the CH structure has good focusing intensity and can focus acoustic waves over a wide range of incidence angles without losing its functionality. With its good focusing capabilities, this new composite lens may open the door to a broad range of applications, including high-precision nondestructive testing (NDT), high-efficiency medical treatment and multidirectional underwater focusing.