An acoustic tractor beam that can bend sound around an obstacle to levitate an object on the other side has been created by researchers in the UK. Dubbed SoundBender, the device combines an ultrasound transducer array with an acoustic metamaterial.
In recent years, researchers have used transducer arrays to build sonic tractor beams that can create complex acoustic holograms to manipulate objects in mid-air. Acoustic metamaterials are engineered materials with structural properties that do not usually occur naturally. They have been used to produce acoustic holograms, bend beams of sound and create static acoustic levitation devices. But the team behind the SoundBender, based at the University of Sussex, say that these technologies have key limitations.
Article by william brown, biophysicist, resonance science foundation research scientist.