A team of researchers from the Universities of Bristol and Sussex in collaboration¹ with Ultrahaptics have built the world's first sonic tractor beam that can lift and move objects using sound waves. Tractor beams are mysterious rays that can grab and lift objects. The concept has been used by science-fiction writers, and programmes like Star Trek², but has since come to fascinate scientists and engineers. Researchers have now built a working tractor beam that uses high-amplitude sound waves to generate an acoustic³ hologram which can pick up and move small objects. 

 

The technique, published in Nature Communications, could be developed for a wide range of applications, for example a sonic production line could transport delicate objects and assemble them, all without physical contact. On the other hand, a miniature version could grip and transport drug capsules or microsurgical instruments through living tissue.

 

Asier Marzo, PhD student and the lead author, said: "It was an incredible experience the first time we saw the object held in place by the tractor beam. All my hard work has paid off, it's brilliant."

 

Bruce Drinkwater, Professor of Ultrasonics⁴ in the University of Bristol's Department of Mechanical Engineering, added: "We all know that sound waves can have a physical effect. But here we have managed to control the sound to a degree never previously⁵ achieved."

 

Sriram Subramanian, Professor of Informatics at the University of Sussex and co-founder of Ultrahaptics, explained: "In our device we manipulate objects in mid-air and seemingly defy gravity. Here we individually control dozens of loudspeakers to tell us an optimal⁶ solution to generate an acoustic hologram that can manipulate multiple objects in real-time without contact."

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