A new Cornell 'nanoguitar,' played by a laser, offers promise of applications in electronics and sensing
The original nanoguitar (top) was made to resemble a Fender Stratocaster. The new, "playable" version is modeled on the Gibson Flying V. Both were made by electron beam lithography, which can create far smaller shapes than earlier methods, at the Cornell Nanoscale Facility. (Although both are shown at about the same size here, the playable guitar is actually about five times larger than the original.) Craighead Group
Copyright © Cornell University
ITHACA, N.Y. -- 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 tiny mechanical devices using techniques originally designed for building microelectronic circuits.
Now, by "playing" a new, streamlined nanoguitar, Cornell physicists are demonstrating how such devices could substitute for electronic circuit components to make circuits smaller, cheaper and more energy-efficient.
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, Nov. 2 to 7 in Baltimore. At the same meeting Harold Craighead, professor of applied and engineering physics at Cornell, presented a plenary talk reviewing the uses of NEMS in biology. Sekaric worked in the Craighead Research Group at Cornell, part of the Cornell Center for Materials Research study of NEMS systems.
NEMS usually refers to devices about two orders of magnitude smaller than MEMS (microelectromechanical systems). Craighead prefers to define NEMS as devices in which the small size is essential for the job, such as those that respond to very small forces or biosensors so small that they can measure the mass of a single bacterium.
Sekaric, now a researcher at IBM's Watson Research Center in Yorktown Heights, N.Y., worked with Cornell graduate student Keith Aubin and undergraduate researcher Jingqing Huang on the new nanoguitar, which is about five times larger than the original, but still so small that its shape can only be seen in a microscope. Its strings are really silicon bars, 150 by 200 nanometers in cross-section and ranging from 6 to 12 micrometers in length (a micrometer is one-millionth of a meter; a nanometer is a billionth of a meter, the length of three silicon atoms in a row). The strings vibrate at frequencies 17 octaves higher than those of a real guitar, or about 130,000 times higher.
The original nanoguitar (top) was made to resemble a Fender Stratocaster. The new, "playable" version is modeled on the Gibson Flying V. Both were made by electron beam lithography, which can create far smaller shapes than earlier methods, at the Cornell Nanoscale Facility. (Although both are shown at about the same size here, the playable guitar is actually about five times larger than the original.) Craighead Group
Copyright © Cornell University
Sounds of the nanoguitar
(Admittedly not great music)
No one can "hear" the nanoguitar, but Cornell researchers have detected the vibrations and electronically scaled them down to audible tones.
"Bugle Call," is played on a single string by selecting and amplifying various harmonics of the string's fundamental tone, just as a bugle is played by selecting harmonics of the resonance of its column of air.
"Cagey," so named because it suggests the chaotic compositions of John Cage, is a short improvisation played by hitting more than one string with separate laser beams.
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Bugle Call
Cagey
For laboratory NEMS research, Cornell physicists use less musical devices like this nanopaddle, which can be set into motion by laser light. Copyright © Cornell University Click on the image for a high-resolution version (512 x 480 pixels, 163K)
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