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#### Tomographic readout of an opto-mechanical interferometer

##### MPS-Authors
/persons/resource/persons40461

Kaufer,  Henning
Laser Interferometry & Gravitational Wave Astronomy, AEI-Hannover, MPI for Gravitational Physics, Max Planck Society;

/persons/resource/persons40510

Westphal,  Tobias
Laser Interferometry & Gravitational Wave Astronomy, AEI-Hannover, MPI for Gravitational Physics, Max Planck Society;

/persons/resource/persons40449

Friedrich,  Daniel
Laser Interferometry & Gravitational Wave Astronomy, AEI-Hannover, MPI for Gravitational Physics, Max Planck Society;

/persons/resource/persons40490

Schnabel,  Roman
Laser Interferometry & Gravitational Wave Astronomy, AEI-Hannover, MPI for Gravitational Physics, Max Planck Society;

##### External Ressource
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##### Fulltext (public)

1205.2241
(Preprint), 425KB

NJoP_14_9_095018.pdf
(Any fulltext), 778KB

##### Supplementary Material (public)
There is no public supplementary material available
##### Citation

Kaufer, H., Sawadsky, A., Westphal, T., Friedrich, D., & Schnabel, R. (2012). Tomographic readout of an opto-mechanical interferometer. New Journal of Physics, 14: 095018. doi:10.1088/1367-2630/14/9/095018.

Cite as: http://hdl.handle.net/11858/00-001M-0000-000E-EBC5-B
##### Abstract
The quantum state of light changes its nature when being reflected off a mechanical oscillator due to the latter's susceptibility to radiation pressure. As a result, a coherent state can transform into a squeezed state and can get entangled with the motion of the oscillator. The complete tomographic reconstruction of the state of light requires the ability to readout arbitrary quadratures. Here we demonstrate such a readout by applying a balanced homodyne detector to an interferometric position measurement of a thermally excited high-Q silicon nitride membrane in a Michelson-Sagnac interferometer. A readout noise of $\unit{1.9 \cdot 10^{-16}}{\metre/\sqrt{\hertz}}$ around the membrane's fundamental oscillation mode at $\unit{133}{\kilo\hertz}$ has been achieved, going below the peak value of the standard quantum limit by a factor of 8.2 (9 dB). The readout noise was entirely dominated by shot noise in a rather broad frequency range around the mechanical resonance.