| AVS 64th International Symposium & Exhibition | |
| MEMS and NEMS Group | Tuesday Sessions |
| Session MN+BI+EM+SS+TR-TuM |
| Session: | Microelectromechanics: Relays to RF/Surfaces in Micro- and Nano- Systems |
| Presenter: | David Czaplewski, Center for Nanoscale Materials, Argonne National Laboratory |
| Authors: | D.A. Czaplewski, Center for Nanoscale Materials, Argonne National Laboratory C. Chen, Argonne National Laboratory D. Lopez, Argonne National Laboratory D.H. Zanette, Centro Atomico Bariloche and Instituto Balseiro S.W. Shaw, Florida Institute of Technology |
| Correspondent: | Click to Email |
Resonant MEMS and NEMS structures are used in a wide variety of applications including mass and force sensing, time keeping, and quantum information. For all MEMS and NEMS resonators, energy is lost every cycle of oscillation to the environment (modeled as a coupled bath). If this energy is not restored by an external source, the amplitude of the resonant motion will decrease toward zero. This well-known effect is commonly referred to as “ring-down”. For linear resonators, the frequency of the resonator will remain constant and the amplitude will decreases exponentially while for non-linear resonators, the amplitude will decrease exponentially and the frequency will simultaneously decrease toward the linear response due to the amplitude-frequency (a-f) effect. However, we demonstrate a non-linear resonator that has constant frequency and an amplitude that does not decay for a given period of time (~ 0.1 s) after discontinuing the restoring energy to the system. We call this time “coherence time” because the amplitude and frequency of the oscillation does not decay when the restoring energy is removed. In essence, the resonator is autonomous during coherence time. Unfortunately or fortunately, this behavior does not violate the second law of thermodynamics. The behavior can be explained by looking at the entire system. We drive a non-linear MEMS resonator to a frequency where the primary mode couples with another internal mode. When the resonator is actively driven, the higher order mode receives energy from the primary mode. When the external energy is discontinued, this energy is restored back to the primary mode allowing the primary mode to continue to oscillate. However, once the energy stored in the higher order mode is depleted (its amplitude is near zero), the behavior of the primary mode begins to “ring-down”. During this talk, I will show characteristics of the coupled modes including operation with constant frequency and a non-decaying amplitude for a period of time with no drive.