Researchers from Tokyo Metropolitan University have developed a new technology which allows non-contact manipulation of small objects using sound waves. They used a hemispherical array of ultrasound transducers to generate a 3D acoustic fields which stably trapped and lifted a small polystyrene ball from a reflective surface. Although their technique employs a method similar to laser trapping in biology, adaptable to a wider range of particle sizes and materials.

Researcher Shota Kondo and Associate Professor Kan Okubo from Tokyo Metropolitan University have come up with a new approach to lift millimeter-sized objects off a reflective surface using a hemispherical array of transducers. Their method of driving the array does not involve complex addressing of individual elements. Instead, they split the array into manageable blocks and use an inverse filter that finds the best phase and amplitude to drive them to make a single trap at some distance from the transducers themselves.

See the video below and articles at SciTechDaily and EurekaAlert.

The paper: “Mid-air acoustic tweezers for non-contact pick up using multi-channel controlled ultrasonic transducer arrays” by Shota Kondo and Kan Okubo, 2 June 2021, Japanese Journal of Applied Physics.
DOI: 10.35848/1347-4065/abfebd