Scientists at ETH Zurich and the Swiss Federal Institute of Technology Lausanne have developed a device that directs sound waves in one direction without wasting energy. This breakthrough sound wave director consists of a disk-shaped cavity with three equidistant ports for sending or receiving sound.
When activated, sound from one port is only heard at a specific second port, not the third. This is achieved by introducing swirling air into the cavity at a precise speed and intensity, creating a synchronized, repeating pattern of sound waves.
The researchers believe that the sound wave director could help them better understand and design future communications technologies. The process used to direct the sound waves not only guides the waves in one direction but the researchers say it also amplifies them.
The researchers made this new discovery by improving upon a 2014 design from the University of Texas at Austin. That particular device suffered immensely from sound dissipation. However, the new device uses self-sustaining oscillations to maintain and even increase the sound waves’ energy so they don’t die out before reaching their destination.
The technology driving the sound wave director could have several applications in new types of noise suppression, communications, and even radar systems. The researchers believe it could even lead to the development of new metamaterials that allow us to manipulate electromagnetic waves.
The researchers believe this concept of “loss-compensated non-reciprocal wave propagation” can be applied to other systems beyond acoustics, too, like light. The group has published their findings on the new discovery in the journal Nature Communications.
In that paper, they discuss how they improved upon the original design to create a sound wave director that doesn’t cause the waves to lose energy as they travel. They also hope that this new design will help others study sound wave propagation and manipulation—like using sound waves to make particles levitate.
