Japanese researchers have developed a novel technique to levitate and manipulate small objects from reflective surfaces using only sound waves. In testing with a 3-millimeter polystyrene ball, the team was able to lift the ball using their array from a reflective surface. It wasn’t terribly reliable, however, as sometimes, the ball would move away from the acoustic chamber rather than become trapped within it.
As Science Alert highlights, engineers Shota Kondo and Kan Okubo from the Tokyo Metropolitan University split a transducer array into blocks, making it more manageable. Next, they employed an inverse filter to recreate sounds based on the acoustic waveform, which makes it easier to tweak the phase and amplitude of each transducer channel to create the desired acoustic field.
“This creates an acoustic trap at only the desired position, and pick up can thus be realized on the rigid stage,” the duo wrote. “To the best of our knowledge, this is the first study to demonstrate non-contact pickup using this approach.”
The resulting acoustic field can be moved around, which in turn moves the particle trapped within it.
The team said they are aiming to improve the robustness of the method in the future in hopes of leading to practical use cases for non-contact pick up. Such a technique, if perfected, could be incredibly useful in the fields of nanotechnology and biomedical engineering as well as within the pharmaceuticals industry.