This is an exciting advancement in the field of acoustics
It is known that intense sound can be produced by electrically-powered nanotubes stretched into sheets, but researchers from University of Texas at Dallas (UT Dallas) have furthered this principle by arranging sheets of carbon nanotubes into “forests” which produce high-quality sound when struck with lasers. This is an exciting advancement in the field of acoustics since it is thought these forests could be used to form invisible wireless speakers that could be embedded into walls, windows, computer screens, cars – the list is endless.
The acoustic properties of electrically-powered nanotubes have been known for some time. Previous studies have shown that sheets of carbon nanotubes are able to produce sound when heated with alternating electrical current. However, the UT Dallas NanoTech research team has found that striking tones can be generated by vertical arrays of nanotube forests, which visually resemble black velvet. Furthermore, they discovered that high-quality sound can be generated when these forests are excited with laser light that is modulated in the acoustic frequency range.
“Nanotubes assemblies of various types are black and highly conductive,” said Dr Mikhail Kozlov, a research scientist and the study’s lead author. “Their dark, conductive surface can be effectively heated with laser light or electricity to induce variations in the pressure of the air around the nanotubes – which we perceive as sound. It’s called the photo- or thermo-acoustic effect, and it’s the same principle Alexander Graham Bell used to produce sound on the first telephone.”