Boldly going where no researchers have gone before.
British researchers from the universities of Bristol and Sussex, in conjunction with Ultrahaptics, have built the world’s first sonic tractor beam — a beam that lifts and moves objects using sound waves. Sriram Subramanian, a Sussex Professor of Informatics, used high-amplitude sound waves to generate an acoustic hologram that can pick up and move small objects.
This cool device allows for the maneuvering of small spherical objects, specifically four-millimeter-wide polystyrene beads, by controlling 64 miniature loudspeakers. The speakers are controlled at a frequency of 40 kilohertz (Khz), which create high-pitched and high-intensity sound waves to levitate the beads.
The tractor beam surrounds the beads with high-intensity sound, which creates a force field capable of not only keeping the beads in place, but also move or rotate them. The team has tested three different shapes of acoustic force fields ranging from one that resembles a pair of fingers, one in which objects become trapped at the core, and one described as a “high-intensity cage” that surrounds the objects and holds them in place from all sides. Surprisingly, each system consumes only nine Watts of power.
“What we have here is what we call an acoustic hologram — or what we have called an acoustic hologram because I think it's the first time it has been used,” Marzo told Reuters. “A traditional hologram it's made of light and you have flat surfaces. Nonetheless it creates a 3D light field. If you remember Star Wars you can see the robot R2D2 and it's broadcasting a 3D spaceship, even from a flat surface. So this is exactly the same; we have a flat surface and we are creating a 3D acoustic field that can surround the particle.”
This is not the first time scientists have tried to create a tractor beam, however, previous examples involved using light. According to Marzo, “I think the only real tractor beam that has been achieved before was with light; it was a very powerful focalized laser and it was able to trap the particles and move it towards the laser, towards the source. However, the particles had to be very small — like around the micrometers and you need to pump a lot of power into the laser.”
Amazingly, this technology could be used for both large and small applications. For example, Marzo said it could be used to create fake gravity in zero gravity environments, like on the International Space Station.
However, the main goal of the technology is to revolutionize surgery, using a miniature tractor beam to transport drug capsules or microsurgical instruments through living tissue. “For me the major application, the best application, would be going smaller and levitating things inside your body and this could be drug capsules, this could be kidney stones, this could be clots or micro surgical instruments, a tiny scalpel, tiny scissors that you could control from the outside without any incision,” said Marzo.
Take a look at the sonic tractor beam in action: