Now a group of researchers from the Universities of Sussex and Bristol, in collaboration with ultrasound technology start-up Ultrahaptics, have created a sonic tractor beam using a single emitter made up of tiny speakers. Acoustic levitation, the ability of sound waves to levitate objects, has been known to science for some time, However, this is the first time that high amplitude ultrasonic sound waves, which aren't even audible to the human ear, have been used to levitate a small polystyrene bead. In the past, acoustic levitation required extremely bulky equipment including multiple speaker banks and/or sound reflectors. But the current sonic levitation technique demonstrated by researchers only utilized a single emitter made up of 64 miniature loudspeakers.
The researchers led by Asier Marzo, have published their technique in the journal Nature Communications on 27 October, 2015. They have developed an algorithm which utilizes three different types of force fields as tractor beams. The first mimics a pair of fingers or tweezers which can hold and rotate the object. The second is an acoustic vortex which traps the object within its core and the last is a high intensity cage-like force field which surrounds the object from all sides and holds it in place. This technique could be used to create a sonic levitation based production line which would assemble delicate parts without any human contact. The technique could also be used to create industrial and home appliances with invisible but tactile control knobs which would be controlled by sound - it may be applied to various consumer and industrial uses, as well as medical surgery.
This is just a start – watch how quickly this “new” technology advances in the next few years.
References: "Holographic acoustic elements for manipulation of levitated objects" - Asier Marzo et al. - October 27, 2015. Nature Communications 6, Article number: 8661 doi:10.1038/ncomms9661