Tuesday, October 27, 2009

"MATERIALS: Hyperlens harnesses metamaterials for ultrasound, sonar"

Invisibility cloaks are giving way to real applications of metamaterials, such as a hyperlens that can focus ultrasound and sonar with eight-times more resolution merely by adding a mechanical attachment, such as the one demonstrated here. Look for commercial ultrasound imagers to retrofit hyperlenses within three years. R.C.J.

Researchers claim that they have harnessed metamaterials to fabricate the world's first acoustic hyperlens, potentially offering an eight-fold increase ultrasound and sonar image resolution. Metamaterials have previously been proposed for sonar invisibility cloaks that hide submarines by bending acoustic waves around them. Researchers at the Energy Department's Lawrence Berkeley National Laboratory say they have demonstrated that metamaterials also can be used for acoustic hyperlenses focused with sub-wavelength accuracy. Berkeley Lab's hyperlens uses metamaterials to focus on objects 6.7 times smaller than the wavelength of the sound wave used. The researchers said the acoustic hyperlens can be further improved to boost the magnification of sound-based imaging technologies such as ultrasound and sonar. The group is currently working on a 3-D ultrasound imaging system that will use pulse-echo technology used to "ping" submarines in sonar applications as well as for medical imaging.