Acoustic Hologram Enhanced Phased Arrays for Ultrasonic Particle Manipulation

By combining phased-array technology with recent developments in acoustic holograms, the authors enhance the capabilities of ultrasonic particle manipulation while reducing the cost. A 3D-printed hologram enables them to create high-fidelity force fields and manipulate small objects along complex paths. Attached to this hologram is an array of independent sound sources; controlling the output delay (phase) of these sources allows movement of the force field in space, yielding noncontact ``tweezers'' that can trap particles of almost any shape. Applications include 3D-bioprinting of cells to create designer tissues, as well as holding microorganisms in place for careful biological study.