People might still be annoyed that we don’t have warp drive yet, but another invention straight out of science-fiction has now become a reality. Researchers from the Universities of Bristol and Sussex, England in collaboration with Ultrahaptics have developed the first sonic tractor beam that can lift and move objects using nothing but sound waves.
The team used a system made of 64 miniature loudspeakers able to create high-pitched and high-intensity sound waves, generating an acoustic hologram that can lift, move, rotate and hold small objects. The system can create three different shapes of acoustic force fields. The first was made to resemble tweezers, the second was a vortex-like structure which trapped the object in the middle, and the last one surrounds the object from all directions and keeps it in place.
This new technology presents the opportunity for far-reaching applications: from mechanical support moving and assembling delicate objects, to medical aid where miniaturized beams could guide drugs through living tissue.
Last year, scientists from the University of Dundee constructed a simple sonic tractor beam, but the newly developed technology gives the user a lot more control on the objects within the beam.
Sriram Subramanian, Professor of Informatics at the University of Sussex and co-founder of Ultrahaptics, said in a statement: "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."
An unprecedented ability to wield sound waves was necessary to reach this sophisticated technology. "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," added Bruce Drinkwater, Professor of Ultrasonics in the University of Bristol's Department of Mechanical Engineering.
The current sonic tractor beam can levitate objects between 0.6 to 4 millimeters in size, and the maximum size for the levitated objects is determined by the frequency of the sound waves – the lower the frequency, the larger the object that can be manipulated. As sound frequencies can be easily changed, there's the potential of using sound at megahertz frequency, to move a cell, down to kilohertz, to lift a beach ball.
"We have some future work on levitating a beach ball from 10 meters away but from my point of view, the really interesting applications are in manipulating small particles that are inside our body," lead author Asier Marzo told IFLScience. "That is possible because sound can travel through water or human tissue. This potentially enables the manipulation of clots, kidney stones, drug capsules, microsurgical instruments or cells inside our body without any incision."
The research is published in Nature Communications.
Image in text: Courtesy of Asier Marzo, Bruce Drinkwater and Sriram Subramanian.