Hannover 2010 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 55: Poster II
Q 55.48: Poster
Thursday, March 11, 2010, 16:00–19:00, Lichthof
Beam Stabilization for Atmospheric Quantum Communication — •Claudia Dürr1,3, Bettina Heim1,2, Dominique Elser1,2, Christoffer Wittmann1,2, Denis Sych1,2, Christoph Marquardt1,2, and Gerd Leuchs1,2 — 1Max Planck Institute for the Science of Light, Erlangen — 2Institute of Optics, Information and Photonics, University of Erlangen-Nuremberg — 3University of Applied Sciences, Munich
We present a free space quantum communication system using continuous polarization states [1]. Weak coherent signal states are polarization-multiplexed with a bright local oscillator in order to perform homodyne measurements. Our atmospheric channel of length 1.6 km produces spatial beam fluctuations which could lead to detection losses [2]. Since losses can be detrimental for continuous-variable quantum states, we compensate for them by using active beam stabilization. For that purpose, the bright local oscillator generates a control signal on a position-sensitive-detector at the receiver. By using a network connection, we feed this signal back to the receiver in order to control the telescope’s tilt.
[1] D. Elser et al., New J. Phys. 11, 045014 (2009)
[2] B. Heim et al., to appear in Appl. Phys. B