Sound waves are, at their simplest, pressure oscillations in one media or another, though we are most familiar with that media being air as that is how we hear. They can also be used to see though, as demonstrated by sonar and sonograms, which reflect sound waves off of objects to determine what they look like. Now researchers at the University of Michigan have found a way to use sound as a non-invasive and potentially painless scalpel.
Focused sound waves have been used in hospitals before, as a means to destroy cancer cells and kidney stones, but never with great precision. Typically this technology is precise only to several millimeters, but the researchers have found a way to make it precise at the micrometer scale. Specifically the researchers are able to focus the light down to a 75 by 400 micrometer area. The researchers achieved this precision with a special lens that converts laser light to mechanical motion, which is not a new phenomenon. What is new are new are layers of carbon nanotubes and polydimethylsiloxane which together amplify the sound waves. When the laser light hits the nanotubes they heat up the polydimethylsiloxane, which expands rapidly as a result, and that amplifies the sound.
The researchers see great potential for this technology, including the potential to use it in painless procedures, by aiming around nerve cells. However this has yet to be proven possible as the technology has not yet been tested in animals.