Acoustic “tractor beam” breakthrough may hold the key to the future of medicine and manufacturing

Vaughn Highfield January 22, 2018

A new breakthrough in ultrasonics has researchers believing we’re not that far away from a reality where large objects, even humans, could levitate through the power of sound alone.

No, this doesn’t mean you’ll be able to fly using ultrasonics like Banshee from X-Men, but a new breakthrough could lead to a world of new possibilities in manufacturing and medicine.

Engineers from the University of Bristol made a breakthrough in how ultrasonics work by using their conical audio waves to contain an object in space that’s larger than any before. By utilising multiple ultrasonic waves, an object can be suspended in the air by sound alone.

The breakthrough works by utilising rapidly fluctuating “tornadoes of sound” to create “twister-like structures with loud sound surrounding a silent core.” The researchers at Bristol then changed the twisting direction of the vortices allowing them to stabilise the wave and increase the size of its silent core. It’s thanks to this technique, and utilisation of a 40kHz wave they were able to levitate an object larger than ever before.

ultrasonic_wave_levitation

In the press release, the breakthrough is referred to as the creation of a tractor beam, but it’s unclear if these ultrasonic waves can actually be used to move objects together or simply suspend them in space. If it can be used for object movement, rather than levitation, the applications for such beams could revolutionise many aspects of our everyday lives.

“Acoustic researchers had been frustrated by the size limit for years, so it’s satisfying to find a way to overcome it,” said Asier Marzo, lead author on the paper from Bristol’s Department of Mechanical Engineering, in a release published alongside the paper. “I think it opens the door to many new applications.”

These applications are incredibly wide-ranging, with Bristol University’s Bruce Drinkwater expressing an interest “the idea of contactless production lines where delicate objects are assembled without touching them.” Other applications could see these ultrasonic waves used in medicine for use in the human body or manufacturing of drugs in a sterile environment.

One interesting application could be for the containment of energy for fusion reactors where it’s imperative that energy isn’t lost through contact with external surfaces.

It’s believed that these ultrasonic waves could be used to aid in the transportation of humans, even providing comforts like invisible seating and air-suspended beds. However, I wouldn’t get too excited about that potential future off the back of this single breakthrough. When researchers talk of levitating the largest object ever held in an ultrasonic wave beam, it’s worth noting that they’re talking about a two-centimetre polystyrene sphere, so we’re still quite a way off suspending an 80kg human with sound alone.

“In the future, with more acoustic power it will be possible to hold even larger objects,” said senior research associate Mihai Caleap. “This was only thought to be possible using lower pitches, making the experiment audible and dangerous for humans.”