New Metamaterials Could Produce Sonar Cloaking Device
Acoustic metamaterial bends sound waves to hide ships from sonar, effectively rendering them sonically invisible
A new material created by researchers can refocus sound around certain objects and effectively render them sonically invisible to sonar. No natural material can do this, so man-made “metamaterials” must be created in order to toy with the laws of physics to essentially bend sound back on itself.
The acoustic metamaterial lens is composed of a planar network of subwavelength Helmholtz resonators. Image courtesy of Nicholas Fang.
The sound-focusing metamaterial-based device developed by Fang’s group is an aluminum array of resonant cavities with dimensions tuned to interact with ultrasound waves. Filled with water, the cavities behave similar to wind instruments such as the flute, which resonates when a stream of air blows across a hole in the instrument. Though the ultrasound system has yet to beat the diffraction limit, it may not be long before they do. “I am sure that we shall not have long to wait,” Imperial College physics professor John Pendry told the MIT Technology Review.
First Acoustic Superlens
An ultrasound lens could be used for high-resolution clinical imaging.
Over the past few years, researchers have developed several materials that bend light in ways that appear to violate the laws of physics, creating so-called superlenses, for ultra-high-resolution optical imaging, as well as invisibility cloaks. Now researchers have demonstrated that the same kind of images and cloaking devices could be made with sound instead of light. Using the first acoustic metamaterial ever produced, the researchers were able to focus ultrasound waves. This represents a significant step toward creating high-resolution ultrasound images and cloaking devices capable of hiding ships from sonar.
Acoustic Super lenses using sound waves and mentamaterials
Sources:
- New Metamaterials Could Produce Sonar Cloaking Device | Popular Science
- medtechinsider » Blog Archive » Acoustic Metamaterial Could Enable Ultrahigh-Resolution Ultrasound Imaging
- Technology Review: First Acoustic Superlens
- Acoustic Super Lenses Using Sound Waves And Mentamaterials - Gizmo Watch
Related:
- Acoustic Cloaking Could Hide Objects from Sonar - MechSE - Illinois
- Nicholas X. Fang - MechSE Department - Illinois
- Focusing Ultrasound with an Acoustic Metamaterial Network
