Beam Shaping in Fourier-Transform Acoustic Systems
Qinxin Zhou, Xuemei Ren, Jie Huang, Zheng Xu, Xiaojun Liu
Abstract
Acoustic beam-shaping techniques have a variety of application scenarios. Traditional phase-only modulation techniques are unable to accurately shape ultrasonic beams that require precise modulation of both amplitude and phase, such as nondiffracting beams. To provide more flexible, simple, and efficient shaping methods, we have developed the Fourier-transform acoustic beam-shaping system. Our proposed system enables the phase-only acoustic beam to reconstruct wave front and optimize its shape for achieving amplitude and phase modulation. We conducted experiments on generating different types of beams using the system. The feasibility of the system was established by generating multifocal beams. Additionally, nondiffracting Weber beams were constructed, with the findings showing that the beam possesses self-healing capability and can travel along a parabolic trajectory. Furthermore, by extending the Fourier transform to the two-dimensional space, we have successfully generated a perfect acoustic vortex beam, which has the same annular intensity profile for any given integer value of the order. Experiments showed that the perfect vortex beam enables the flexible and accurate manipulation of single and multiple particles. We conclude that the Fourier-transform acoustic system is a convenient way for acoustic beam shaping and has broad application prospects, such as drug delivery and high-speed acoustic communication.