Researchers at University of Minnesota have developed a way to freely manipulate objects with the help of ultrasound waves.
“We have known for a while that waves and light and sound can manipulate objects. What sets our research apart is that we can manipulate and trap much bigger objects if we make their surface a metamaterial surface, or a ‘meta-surface,’” said Ognjen Ilic, senior author of the study and the Benjamin Mayhugh Assistant Professor in the University of Minnesota Department of Mechanical Engineering.
Scientists have previously demonstrated that light and sound waves can manipulate objects, the objects have always been smaller than the wavelength of sound or light, or on the order of millimeters to nanometers, respectively. The University of Minnesota team has developed a method that can move larger objects using the principles of metamaterial physics.
Metamaterials are artificially designed materials that can interact with waves like light and sound. By placing a metamaterial pattern on the surface of an object, the researchers were able to use sound to steer it in a certain direction without physically touching it.
“When we place these tiny patterns on the surface of the objects, we can basically reflect the sound in any direction we want. And in doing that, we can control the acoustic force that is exerted on an object.” Using this technique, the researchers can not only move an object forward but also pull it toward a source—not too dissimilar from the “force” described in Star Wars.
“Contactless manipulation is a hot area of research in optics and electromagnetism, but this research proposes another method for contactless actuation that offers advantages that other methods may not have,” said Matthew Stein, first author on the paper and a graduate student in the University of Minnesota Department of Mechanical Engineering. “Also, outside of the applications that this research enables, expanding upon our knowledge of physics is just a very exciting thing to do in general.” Researchers aim to test out higher frequencies of waves and different materials and object sizes in the future.
Reference : Matthew Stein et al, Shaping contactless radiation forces through anomalous acoustic scattering, Nature Communications (2022). DOI: 10.1038/s41467-022-34207-7