Phys.org November 12, 2019
Though the idea of engineering materials or surfaces to strategically refract sound waves is well-established, most existing designs are static. An international team of researchers (China, University of Nebraska) has designed a tunable metasurface with Helmholtz resonance. Moving sliders in the design allow full phase shift with a high transmission ratio in a broad frequency bandwidth. The design can be used for tunable wave front redirection, focusing with varying wavelengths and sound source illusion, as shown in numerical and experimental examples. The technique may be used in applications that range from magnifying signals to disorienting adversaries…read more. TECHNICAL ARTICLE
By extending or retracting T-shaped sliders to narrow or widen a series of resonators can dynamically redirect sound waves passing through the surface. Credit: Scott Schrage | University Communication