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Q: Fachverband Quantenoptik und Photonik
Q 1: Micro Mechanical Oscillator 1
Q 1.3: Vortrag
Montag, 14. März 2011, 11:00–11:15, HSZ 02
Tuning the quality factor of a miromechanical membrane oscillator — •Andreas Jöckel1, Maria Korppi1,2,3, Stephan Camerer2,3, Matthias Mader2, David Hunger2,3, Theodor W. Hänsch2,3, and Philipp Treutlein1,2,3 — 1Departement Physik, Universität Basel, Switzerland — 2Ludwig-Maximilians-Universität, München, Germany — 3Max-Planck-Institut für Quantenoptik, Garching, Germany
We report on the characterization and tuning of the mechanical modes of high-Q SiN-membrane oscillators. 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 rather 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 intrinsic stress.
The frequencies of several modes were measured with a Michelson interferometer. We observe that the Q-factor changes dramatically while tuning and reveals resonances in the mechanical dissipation, which allows us to tune the Q-factor over two orders of magnitude. With this technique we achieve an improvement over the bare membrane Q-factor.
Another way of improving the properties of these membranes lies in structuring them with a focused ion beam (FIB) in order to reduce their mass, or applying mirrors to increase the reflectivity.