Stuttgart 2012 – scientific programme
Parts | Days | Selection | Search | Updates | Downloads | Help
Q: Fachverband Quantenoptik und Photonik
Q 16: Präzisionsmessungen und Metrologie 3
Q 16.10: Talk
Monday, March 12, 2012, 18:45–19:00, V7.03
A membrane in a Michelson-Sagnac interferometer with balanced homodyne detection readout — •Andreas Sawadsky, Henning Kaufer, Ramon Moghadas, Daniel Friedrich, Tobias Westphal, and Roman Schnabel — Max-Planck-Institut für Gravitationsphysik (Albert-Einstein-Institut) and Institut für Gravitationsphysik, Leibniz Universität Hannover, Hannover, Germany.
Using a balanced homodyne detector we measure a broadband shot noise limited displacement of a silicon nitride membrane with a mechanical Q-factor of 6 · 105 in a Michelson-Sagnac interferometer. Thereby we achieved a displacement sensitivity of 2 · 10−16 m/√Hz above 50 kHz. We showed that, as expected, thermal noise is only present in amplitude quadrature by performing a zero-span measurement exactly at resonance and varying the homodyne readout phase. By implementing a signal recycling mirror in the interferometer output port we could enhance the displacement sensitivity by a factor of 50 at an input power of 1 mW.