A team of researchers from the Universities of Bristol and Sussex in collaboration 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 Trek, 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 acoustic 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 Ultrasonics 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 previously 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 optimal solution to generate an acoustic hologram that can manipulate multiple objects in real-time without contact."
The researchers used an array of 64 miniature loudspeakers to create high-pitch and high-intensity sound waves. The tractor beam works by surrounding the object with high-intensity sound and this creates a force field that keeps the objects in place. By carefully controlling the output of the loudspeakers the object can be either held in place, moved or rotated.
The team have shown that three different shapes of acoustic force fields work as tractor beams. The first is an acoustic force field that resembles a pair of fingers or tweezers. The second is an acoustic vortex, the objects becoming stuck-in and then trapped at the core and the third is best described as a high-intensity cage that surrounds the objects and holds them in place from all directions.
Previous work on acoustic studies had to surround the object with loudspeakers, which limits the extent of movement and restricts many applications. Last year, the University of Dundee presented the concept of a tractor beam but no objects were held in the ray.
Explore further: Photonics: Beam me up
More information: DOI: 10.1038/ncomms9661
krundoloss
docile
Oct 27, 2015Lischyn
mikael_murstam
No this is acoustic suspension. They are building a high pressure "hologram" to keep it in place. The tractor beam part isn't really new. It simply sits in a node.
krundoloss
But in the end, you are using air pressure to make something float, just like be Bernoulli effect. I was just drawing parallels.
antigoracle
docile
Oct 27, 2015jeffrm
swordsman
So why not do this with electromagnetic waves in the near field?
TychoKrafft
Alexander_IK
bluehigh
Indeed, go ahead.
antialias_physorg
Much more than that. In material sciences it is often crucial to keep the test-material pure. Especially when your test material is hot you have contamination issues with the vessel you're heating it in. Keeping such material afloat and/or being able to move it to where it can interact with another set of material under very controlled conditions in an inert atmosphere (e.g. Argon gas) would be incredibly useful.
The power requirements are immaterial, as the probe-substances you're usually working with are very small.
There's already some similar works being done.
http://www.iflsci...istances
s-l-y