Science Alert July 26, 2021
There are significant limitations hindering acoustic tweezers for broad practical application. Although hemispherical arrays of acoustic transducers can be used to create the sound trap, creating just the right sound field to lift an object and move it far from the transducers is very difficult if there is a surface that reflects sound. Researchers in Japan have developed a technique splitting the transducer array into blocks and used an inverse filter to reproduce sounds based on the acoustic waveform. This helps optimize the phase and amplitude of each transducer channel to produce the desired acoustic field. This field along with the trapped particle can be moved around. Using this array, the researchers were able to pick up a piece of styrofoam from a mirrored surface. Although it is not very reliable the work represents a step forward in contactless pickup from a reflective surface… read more. Open Access TECHNICAL ARTICLEÂ
Levitating an object (l) and a schematic of the array. Credit: Japanese Journal of Applied Physics, Volume 60, Number SDDD61, 2021Â