Researchers at University of Illinois have invented world’s first acoustic superlens. This could be used for high-resolution ultrasound imaging, non-destructive structural testing of bridges and buildings, and underwater stealth technology.
The research was led by Nicholas Fang, Professor of mechanical science and engineering at Illinois. Ultrasound waves were successfully focussed through a flat metamaterial lens on a place about half the width of a wavelength at 60.5 kHz using a network of fluid-filled Helmholtz resonators. According to the outcome, the acoustic system is similar to an inductor-capacitor circuit.
The transmission channels behave like a series of inductors. Helmholtz resonators, which Fang has described as cavities that hold resonating waves and swing at some sonic frequencies as a musical instrument would, behave like capacitors. Fang said that acoustic imaging is similar to optical imaging just as bending of sound is similar to bending of light.
Shu Zhang, graduate student at University of Illinois, who has co-authored the research paper, said that acoustic imaging is safer than optical and X-ray imaging and hence sonography is used ion pregnant woman. Acoustic imaging can also be useful to detect tumours.
Fang said that application of acoustic imaging goes beyond medicine. In non-destructive testing, the structural soundness of a building or a bridge could be scrutinised for hairline cracks with the help of acoustic imaging. Other serious defects that are not visible to the naked eye or that go undetected by optical imaging could also be checked.
Fang said that acoustic imaging could also be used in underwater stealth technology, maybe even act as a camouflage for submarines.