Rostock 2019 – wissenschaftliches Programm

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Q: Fachverband Quantenoptik und Photonik

Q 58: Poster: Quantum Optics and Photonics III

Q 58.27: Poster

Donnerstag, 14. März 2019, 16:15–18:15, S Atrium Informatik

Parametrically Damped High-Q Mechanical Pendulum with Interferometric Readout — •Daniel Hartwig and Roman Schnabel — Institut für Laserphysik und Zentrum für Optische Quantentechnologien, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany

Low-frequency high-precision optomechanical experiments like interferometric gravitational-wave detectors rely on test masses that are suspended as pendula with very low mechanical friction to isolate them from environmental perturbations and measure extremely small distance changes through interferometry. This poster describes a model setup for such a pendulum and evaluates the performance of an active oscillation damping system that relies only on parametric damping. This means modulating one or more of the oscillation parameters and not exerting any forces in the direction of movement. In this case only the resonance frequency is modulated by vertically accelerating the pendulum suspension to reduce the oscillation amplitude. The precise readout of oscillation parameters necessary for parametric damping is provided by an optical measurement system that uses interferometry and displacement measurement on a laser beam reflected by the test mass. With this system a reduction of the pendulum's quality factor from 3300 to 930 could be achieved. The minimum reachable oscillation amplitude was limited by seismic noise to 8 μm peak-to-peak.