Six years ago Cornell University researchers built the world’s smallest guitar – about the size of a red blood cell – to demonstrate the possibility of manufacturing miniature mechanical devices. Now, they have designed one five times bigger that can be played by a laser beam!
Lidija Sekaric, who built the new, playable nanoguitar while an Applied Physics graduate student at Cornell, described the project, along with other materials and device research in nanoelectromechanical systems (NEMS), at the 50th International Symposium and Exhibition of the American Vacuum Society, between November 2 and 7 in Baltimore, MD.
The ‘strings’ of the guitar are really silicon bars, 150 by 200 nanometres in cross-section that range from 6 to 12 micrometres in length. Since they actually vibrate at frequencies 17 octaves higher than those of a real guitar, no one can actually ‘hear’ the nanoguitar, but the Cornell researchers have detected the vibrations from the ‘strings’ and electronically scaled them down to audible tones.
To make them vibrate, researchers ‘hit’ the strings with a focused laser beam. When the strings vibrate they create interference patterns in the light reflected back, which can be detected and then electronically converted down to audible notes. The device can play only simple tones, although chords can be played by activating more than one string at a time.
The ability to make miniature objects vibrate at very high frequencies offers many potential applications in electronics. Nanoscale objects can be made to vibrate at radio frequencies (up to hundreds of megaHertz) and so can be a substitute for other components in electronic circuits. Cell phones and other wireless devices, for example, usually use the oscillations of a quartz crystal to generate the carrier wave on which they transmit or to tune in an incoming signal. A tiny vibrating nanorod might do the same job in vastly less space, while drawing only milliwatts of power.
If you want to hear the ‘music’ from the Cornell guitar, click <a href=’http://www.news.cornell.edu/releases/Nov03/NEMSguitar.ws.html’>here</a> to go to the Cornell site. Jimmy Page eat your heart out.