Hannover 2013 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 66: Quantum effects: Entanglement and decoherence II

Q 66.4: Talk

Friday, March 22, 2013, 15:00–15:15, A 310

Quantum-Dense Read-Out for Interferometric Measurements — Melanie Meinders, •Sebastian Steinlechner, Jöran Bauchrowitz, Helge Müller-Ebhardt, Karsten Danzmann, and Roman Schnabel — Institut für Gravitationsphysik, Leibniz Universität Hannover and Max-Planck-Institut für Gravitationsphysik (Albert-Einstein-Institut), Callinstr. 38, 30167 Hannover, Germany

The sensitivity of interferometric measurements is affected by scattered, frequency shifted photons, so-called parasitic interferences [1]. In gravitational-wave detectors, parasitic interferences are possibly already a limiting factor in the lower audio-band. Future detectors that use higher laser powers will even be stronger disturbed by this kind of noise. In this talk we present a new read-out scheme which allows for the detection of two orthogonal quadratures with uncertainties below that of the meter's ground state. In contrast to science signals in the phase quadrature, parasitic signals due to scattered light have an arbitrary orientation in phase space. Therefore, our read-out scheme can be utilized to identify such signals. The scheme uses entangled, two-mode-squeezed states of light and was experimentally demonstrated on the basis of a table-top Michelson interferometer. In our setup a non-classical noise suppression of ~6dB was achieved in both quadratures.

[1] H. Vahlbruch, S. Chelkowski, K. Danzmann, R. Schnabel, Quantum engineering of squeezed states for quantum communication and metrology, New J. Phys. 9, 371 (2007).