Ultrasound Noncontact Particle Manipulation of Three-dimensional Dynamic User-specified Patterns of Particles in Air

Abstract

Ultrasound noncontact particle manipulation (NPM) is based on the acoustic radiation force associated with an ultrasound wave field, and enables a myriad of engineering applications with the ability to noninvasively manipulate particles in a fluid medium. We use multiple phased arrays of ultrasound transducers to dynamically move a 3D pattern of particles along a userspecified trajectory following a sequence of affine transformations. We numerically simulate and experimentally validate the NPM method using spherical expanded polystyrene particles in air, and observe good quantitative agreement. The ultrasound NPM method enables dynamic control over the user-specified pattern of particles in three dimensions. Hence, this experimental demonstration shows that ultrasound NPM can be implemented in engineering applications, such as container-less transport and measurement techniques, and manufacturing of engineered materials.

Holographic acoustic tweezers

“…Recent advances have enabled the dynamic positioning of acoustically trapped particles in one- (28), two- (21), and three dimensions (30–32); however, the particles were moved as a group, with no individual particle control. Acoustic radiation force devices using 3D printed lenses have also been used to produce complex patterns of particles (33), but these patterns were static and 2D.…”

Self-Navigated 3D Acoustic Tweezers in Complex Media Based on Time Reversal

“…Acoustic tweezers can be broadly classified into two categories [ 19 ], i.e., collective tweezers, which manipulate multiple particles undergoing the same behaviour [ 20 ], and selective tweezers, which create various traps that independently manipulate a subgroup of particles undergoing different behaviours [ 21 – 23 ]. Recently, artificial acoustic structures have been applied for complex beam generation and acoustic tweezers, such as waveguiding obtained by a superhydrophobic acoustic metasurface [ 24 ], generation of acoustic acceleration beams via flexible active surfaces [ 25 ], superoscillation wave packets using a metalens [ 26 ], realization of sound deceleration with helical-structured acoustic metamaterials [ 27 ], and fine acoustic manipulation via lossy metamaterials [ 28 ].…”

“…While the 3D acoustic tweezers showed effective performance in the air [ 21 , 23 , 31 , 33 ], for several reasons, it was rarely replicated in water, wherein the acoustic impedance is close to that of the human tissue. Currently, acoustic tweezers in water are mainly implemented using standing surface acoustic waves (SSAWs) [ 34 , 35 ], which are commonly generated by interdigitated transducers.…”

Acoustic Hologram Enhanced Phased Arrays for Ultrasonic Particle Manipulation

“…This effect is most well known in optics but has previously been demonstrated successfully in underwater ultrasound using threedimensional (3D) printed holograms [3]. In ultrasound, the traditional technique for generating a desired sound field is to use a phased array consisting of a number of independently controlled elements [4][5][6][7][8][9]. However, the hologram offers two key advantages; the first is the simplification of the driving electronics, as it only requires a single channel [10], and the second is the increased phase fidelity, which is only limited by the print or machining resolution.…”