Yoichi Ochiai, Takayuki Hoshi and Jun Rekimoto – scientists at the University of Tokyo – have created a way to levitate objects, in a very precise way, using sound.
An ultrasound standing wave is capable of suspending small particles at its sound pressure nodes. This method has been used previously to levitate lightweight particles, small creatures, and water droplets.
The new system uses a three-dimensional array of speakers, allowing for controlled levitation & movement of objects.
Here’s a demo of the three-dimensional acoustic levitation in action:
The acoustic axis of the ultrasound beam in previous studies was parallel to the gravitational force, and the levitated objects were manipulated along the fixed axis (i.e. one-dimensionally) by controlling the phases or frequencies of bolted Langevin-type transducers. In the present study, millimetre-sized particles were levitated and moved three-dimensionally by localized ultrasonic standing waves, which were generated by ultrasonic phased arrays.
The new manipulation system has two original features:
- One is the direction of the ultrasound beam, which is arbitrary because the force acting toward its centre is also utilised.
- The other is the manipulation principle by which a localised standing wave is generated at an arbitrary position and moved three-dimensionally by opposed and ultrasonic phased arrays.
Check it out and let us know what you think of this!