PhD student from the University of Bristol and Sussex, Asier Marzo, and his team of researchers have built a sonic tractor beam which creates an acoustic hologram that does not require any physical contact by using a flat surface to generate a 3D acoustic field surrounding a given particle. This device is created by individually controlling 64 miniature loud speakers with a frequency of 40 kilohertz (KHz) to produce high-pitched and high intensity soundwaves that can in turn, levitate small spherical objects and expanded polystyrene beads up to 4 millimeters in diameter. The tractor beam surrounds the polystyrene beads with a force field that allows the balls to stay in place without falling even when the device is rotated, which then the user is able to move the beads with the individual high-intensity speakers.
Earlier developments of the tractor beam technology primarily used light as its main component in its device. Marzo and his team thought otherwise.
"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. So this is the real first acoustic tractor beam and it's nice because acoustic tractor beam, acoustic manipulation, and needs much less power and it's more powerful in terms of the materials that it can trap," said Marzo.
Marzo believes this device could be established for many different applications. His team of researchers and him are certainly taking this to the next level.
"Basically one of our future projects aims at levitating something that's like a beach ball ten meters away and we think this could be very useful for zero gravity environments, like under water or in the International Space Station. If you check videos everything is floating around, water the nuts, screws, everything is adrift uncontrollably, so if you can create fake gravity with this device it would help a lot the astronauts,” said Marzo. "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."