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Q: Fachverband Quantenoptik und Photonik
Q 6: Mikromechanische Systeme
Q 6.4: Vortrag
Montag, 12. März 2012, 11:15–11:30, V7.02
Spectroscopy of mechanical dissipation in micro-mechanical membranes — •Andreas Jöckel1, Maria Korppi1, Matthew T. Rakher1, Matthias Mader2, David Hunger2, Stephan Camerer2, and Philipp Treutlein1 — 1Departement Physik, Universität Basel, Schweiz — 2Institut für Physik, LMU München, Deutschland
We report on the characterization and tuning of the mechanical modes of high-Q SiN-membrane oscillators [1]. Such membranes are used in many optomechanical experiments and have Q-factors up to 107 with frequencies in the hundreds of kHz regime and masses of a few ng, resulting in large ground state and thermal amplitudes. We show that the membrane eigenfrequencies can be tuned by locally heating the membranes with laser light, resulting in a release of tensile stress. We observe that the Q-factor changes in a reproducible way by more than two orders of magnitude as a function of membrane frequency and reveals distinct resonances. We show that these resonances can be explained by coupling to localized frame modes. Away from the resonances, the Q-factor is independent of frequency. Higher order modes show the same maximum Q, but different coupling strengths to the frame.
[1] Appl. Phys. Lett. 99, 143109 (2011)