Science Daily March 7, 2019
To break the law of reflection with sound waves, an international team of researchers (Finland, USA – Duke University) designed a meta-mirror out of plastic with precisely etched channels on the surface of the metamaterial. Between the meta-mirror’s shape and the depth of its channels, the interference pattern results in the sound wave reflecting in a desired direction without any of its energy being absorbed or scattered in an unwanted direction. In demonstration the device reflected a soundwave traveling directly toward it at 3,000 Hertz and perfectly reflects it at an angle of 70 degrees. They plan to design devices that can reflect different frequencies in different directions including underwater. The research shows that metasurfaces are a versatile platform for arbitrary control of reflection…read more. Open Access TECHNICAL ARTICLEÂ
The ‘meta-mirror’ was carefully engineered to make a sound wave coming straight at it reflect at a different angle with zero scattering losses. Credit: Steve Cummer, Duke University