The Beauty of Acoustic Levitation (Video)


Acoustic Levitation: Three-Dimensional Mid-Air Acoustic Manipulation

It’s very fascinating to see new progress being made in the area of acoustic levitation, which will see far-reaching value-adding applications in chemical and biological processes. Before we look at an interesting video, let’s talk about what it is.

Defining Acoustic Levitation

Wikipedia defines acoustic levitation as follows:

 “Acoustic levitation is a method for suspending matter in a medium by using acoustic radiation pressure from intense sound waves in the medium. Acoustic levitation is possible because of the non-linear effects of intense sound waves.

Some methods can levitate objects without creating sound heard by the human ear such as the one demonstrated at Otsuka Lab.

By 2013, acoustic levitation had progressed from motionless levitation to controllably moving hovering objects; an ability useful in the pharmaceutical and electronics industries.

There is no known theoretical limit to what acoustic levitation can lift given enough vibratory sound, but current technology can only lift a few kilograms.”

A Multitude of Applications

The ability to levitate multiple objects and manipulate them in a 3D space will find many useful applications in chemistry and biology as well as science overall. There are a lot of chemical and biological processes that can be disrupted by contact with a surface and acoustic levitation is the optimal solution to alleviate that issue.

The fact that levitation can be achieved without the need for magnetism or buoyancy is a great advantage for science. So instead of being limited to magnetic objects, scientist can react anything by leveraging levitation.

Three-Dimensional Mid-Air Acoustic Manipulation

We found a fascinating video demonstrating the beauty of the latest advances in acoustic levitation.

The research team at the University of Tokyo employ ultrasonic speakers at a sound frequency that is not audible to humans.

On Google+, Martijn Vreugde explains the sound-based levitation technology used:

“The essence of levitation technology is the countervailing of gravity. It is known that an ultrasound standing wave is capable of suspending small particles at its sound pressure nodes and, so far, this method has been used to levitate lightweight particles, small creatures, and water droplets.

The acoustic axis of the ultrasound beam in these 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, we considered extended acoustic manipulation whereby millimetre-sized particles were levitated and moved three-dimensionally by localised ultrasonic standing waves, which were generated by ultrasonic phased arrays. Our 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. We experimentally confirmed that various materials could be manipulated by our proposed method.”

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