Cornell University researchers have built the worlds smallest playable guitar. The nanoguitar has silicon bars for 'strings'. The strings are 150 by 200 nanometres in cross-section and range from 6 to 12 micrometres in length. Although humans can’t hear them as they vibrate at frequencies 17 octaves higher than those of a real guitar, the researchers have detected the vibrations from the strings and electronically shifted them to audible tones.
Strings are played by hitting them with a focused laser beam. The vibrating strings create interference patterns in the reflected laser light which can be read and converted to sound.