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Scientists from Tokyo Metropolitan University have presented a new technology that allows you to move small objects without contact using sound waves. They published the results of their work in the “Japanese Journal of Applied Physics”.
How does the new technology presented by Japanese scientists work?
In their work, the scientists recalled that millimeter-sized objects can be captured without contact using optical tweezers, which includes a focused laser beam. In turn, acoustic tweezers use the force of acoustic radiation created by ultrasonic waves to capture. At the same time, acoustic tweezers are better suited for capturing particles of different sizes than optical tweezers. However, for such tweezers to work effectively, complex electrical control is necessary.
Scientists have proposed using hemispherical arrays of ultrasonic transducers that can create acoustic traps without complex control systems. In their study, they used a hemispherical array of ultrasonic transducers to create three-dimensional acoustic fields that were able to capture and lift a small polystyrene ball from a reflective surface.
The method involves splitting the array into controlled blocks and using an inverse filter that finds the best phase and amplitude to force them to create a single trap at some distance from the converters themselves. Thus, the development of Japanese scientists resembles the method of laser capture, which is used in biology, but the novelty can be applied to particles of different sizes and different materials.
Despite the fact that scientists have yet to solve problems with particle retention, in the future the new technology will be able to become a tool for use in laboratories and in industry.