“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.”
With laser excitation, no electrical contact with the nanotube speaker is required, making the speakers wireless.
“Speakers made with carbon nanotube sheets are extremely thin, light and almost transparent,” Kozlov said. “They have no moving parts and can be attached to any surface, which makes the surface acoustically active. They can be concealed in television and computer screens, apartment walls, or in the windows of buildings and cars. The almost invisible strands form films that can ‘talk.’”
In addition to filling a room with sound from invisible speakers, nanotube speakers could easily cancel sound from the noisiest neighbor or dim the roar of traffic rushing past a neighborhood, using the same principles as current sound-canceling technologies.
“The sound generation by nanotube sheets can help to achieve this effect on very large scales,” Kozlov said.
Walid Damouny on 18 Feb 10"Basically, any computing device (or switch, or router) that is based on light requires a nonlinear interaction between different light beams, but light doesn't like to do nonlinear stuff. With current technology, you can get efficient nonlinear optical interactions, but the hardware is kind of bulky or very delicate. Not the sort of thing you want to put in a billion devices. What my friends in Barcelona have demonstrated is that it's possible to create a relatively efficient optical nonlinear interaction in a nano-structured metallic surface. "
