Laser-powered carbon nanotube speakers! They'll fit in walls and windows, and can noise-cancel ambient rackets. Or blast some music.
"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.'"
The research, published in the Journal of Applied Physics, expands on previous work that noted carbon nanotubes can make noise when AC power used; this new paper is all about the specific tones that "black velvet" forests of nanotubes can make when tuned lasers heat the tubes to create thermo-acoustic effects. [UTDallas]