Lévitation acoustique

Alright, to go deeper and understand the subject more, let's see the experiment realized by Japanese scientists. So now, we know what acoustic levitation is. However, to realize their experience, the researchers used a new technology that is an evolution of the acoustic levitation: it's called “the tweezers of sound”.

What's different here? This time we're not limited only to levitate an object, we can trap, lift and move the particle in a stable way. And there's more, the tweezers of sound allow for objects to be picked up without any physical contact from the beginning to the end. That is not possible with acoustic levitation.

Basically, the tweezers of sounds use small devices known as “ultrasonic transducers” to convert a received electrical signal into ultrasound, nothing different here. Except this time the transducers are set up in a way that allows us to move the particle.

Let's go into details: the frequencies of the waves emitted by the transducers are continually changed; and remember, we said that to levitate an object and to trap it is possible because of the frequency used. By altering these frequencies every time, the particle is able to move. A particle levitates at the nodes of a standing wave, then if we change the signal frequency (the waves cancel each other on another place as a result, it creates a new nod), the nodes will move and that's why the object too. It's forced to follow the movement of the nodes.

Changing the frequency of a wave allows the transfer of the particle to other nodes, which creates movement. However, the motion of the particle is permitted only in one way.

One question remains that you may ask yourself. What's the point of doing all of that? Because at the end of the day, it's not useful for any of us to know or have the ability to levitate a little thing in centimeters with sounds. In addition, other technologies with the same principle exist, such as magnetic levitation. But let me tell you that acoustic levitation is more useful than you can imagine.

The first interesting thing about this technology is that any kind of materials can be levitated: liquids, metal, gas, even insects, unlike the magnetic levitation. (Anything with enough acoustic contrast from the medium can lift and trap). And it's really used for biological stuff to analyze or make new drugs more effective. Still in medicine, we might have the possibility of injecting patients' drugs in the form of micro-bubbles controlled by the doctor inside the patient's body.

They would be guided to a specific location of your body for example if you have to heal, I don't know your head. This would lead to the very local release of nanoparticles for treatment purposes.

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