US scientists report the development of an acoustic lens that could lead to an eightfold improvement in the resolution of medical ultrasound scanners. The product of researchers at the Department of Energy’s Lawrence Berkeley National Laboratory, the acoustic “hyperlens” can capture information contained in evanescent waves, which contain far more details than the propagating waves that conventional lenses target. “We have successfully carried out an experimental demonstration of an acoustic hyperlens that magnifies sub-wavelength objects by gradually converting evanescent waves into propagating waves,” says Xiang Zhang, a principal investigator with Berkeley Lab’s Materials Sciences Division and director of the Nanoscale Science and Engineering Center at the University of California, Berkeley (UC Berkeley). “Our acoustic hyperlens relies on straightforward cutoff-free propagation and achieves deep subwavelength resolution with low loss over a broad frequency bandwidth,” Zhang says.
By manipulating the sound waves, the researchers are able to resolve details smaller than one sixth of the length of the waves themselves, bringing into view much smaller objects and features than can be detected using current technologies. “Directly applied to current ultrasound pulse-echo technology, the hyperlens would allow the use of lower input frequency, which in turn would increase the penetration depth and allow physicians to see, for example, smaller tumors or finer features of larger objects that could help them identify other abnormalities,” Zhang says.
More information on the research is available from Berkeley Lab’s Materials Sciences Division.
Last year on this blog, we covered Xiang Zhang’s optical metamaterials research.Brian Buntz