"OPTICAL: NEMS tunes the 'most sensitive' accelerometer"
By coupling a nanoscale etched diffraction grating to an optical sensor, Sandia National Laboratories researchers have demonstrated an accelerometer that they say is the most sensitive in the world. The nanoelectromechanical system (NEMS) could measure vibrations as low as 10 nano-G's, compared with the 100 milli-G vibrations measurable with today's accelerometers, by making mechanical motions as small as 10 nanometers visible to the naked eye. "Because the wavelength of light from our laser is much smaller than the dimensions of our [diffraction] grating, very very small motions have a disproportionate effect," said Sandia researcher Dustin Carr. Team member Bianca Keeler will describe the work later this month at the SPIE Optics East convention in Philadelphia. Today's best integrated accelerometers, such as those that trigger automotive air bags, can detect hundreds of milli-G's. But many unfulfilled apps need more-sensitive accelerometers, such as those that can anticipate earthquakes or sense a skid where the back end of a car is moving in a different direction than the front end.