Tuesday, 26 June, 2012
Group seminar LMU: Integrated transduction and coherent control of high Q nanomechanical systems
Tuesday, 26.06.2012 10:00 a.m. (s.t.) in H107, Fakultät für Physik, LMU
Eva Weig, LMU
Nanomechanical resonators, freely suspended bridges with nanoscale cross-sections, are receiving an increasing amount of attention both in fundamental experiments and sensing applications. In particular, pre-stressed silicon nitride is explored as a high Q material for nanomechanical systems (NEMS): As a consequence of the intrinsic tensile stress of the nitride film, room temperature quality factors of several 100,000 are observed in the 10 MHz eigenfrequency range. To take advantage of the large quality factor, non-dissipative transduction and manipulation schemes have to be developed which do not introduce extra damping.
We employ optically or electrically induced gradient forces to implement dielectric transduction as an efficient way to actuate and probe high Q nanomechanical resonators and to control the resonator eigenfrequency. The displacement sensitivity can be enhanced considerably by taking advantage of near-field coupling to a cavity, which, at the same time allows to benefit from back-action induced dynamics, enabling to cool the Brownian motion or to initiate cavity-pumped self-oscillation. For example, a realization of such a hybrid nanomechanical system incorporating a room temperature microwave cavity offers a plug and play solution for all-integrated transduction, and can be employed to probe the dynamics of two strongly coupled resonator modes.