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Researchers from University of Wisconsin-Madison have unveiled a new acoustic metamaterial capable of moving and rotating objects underwater—without any physical contact. The innovation uses only sound waves to exert force, offering a precise and non-invasive method of control that could reshape underwater operations and medical technologies alike.
At the core of this development is a specially designed surface patterned with microscopic sawtooth structures. According to Interesting Engineering, when sound waves from multiple sources strike this surface, they reflect in controlled directions. This creates carefully directed acoustic radiation forces, strong enough to move or spin objects that are either floating or submerged.
The technology operates without mechanical components or tethered tools. Objects can be manipulated remotely in water, simply by adjusting the direction and intensity of incoming sound waves. Researchers demonstrated full motion control—including linear movement and rotation—by attaching this metamaterial to test objects.
The system’s potential applications are broad. In underwater engineering, it could enable hands-free assembly of structures or components in environments too delicate or hazardous for traditional tools. In medicine, the same principles could one day allow for non-invasive delivery of medication or even remote surgery using sound to guide small instruments or particles inside the body.
Creating a material with the right acoustic properties and fine structural detail was a challenge. Existing manufacturing methods either lacked the resolution needed or were too costly for practical use. To address this, the research team developed a fabrication process that delivers both high precision and affordability, while ensuring a strong acoustic contrast with water—an essential property for effective underwater control.
This development builds on growing interest in acoustic metamaterials, which can manipulate waves in ways conventional materials cannot. Unlike conventional robotics, which rely on direct contact and mechanical movement, this sound-based approach opens up possibilities for remote, damage-free manipulation in confined or sensitive environments.
While still in the experimental phase, the technology shows promise for next-generation underwater systems. The research was presented at the joint 188th Meeting of the Acoustical Society of America and the 25th International Congress on Acoustics.
