Parts | Days | Selection | Search | Downloads | Help
Q: Fachverband Quantenoptik und Photonik
Q 48: Quanteninformation: Quantenkommunikation I
Q 48.4: Talk
Thursday, March 5, 2009, 14:45–15:00, Audi-B
Free space quantum key distribution with coherent polarization states — •Bettina Heim1, Dominique Elser1, Tim Bartley1,2, Christoffer Wittmann1, Denis Sych1, and Gerd Leuchs1 — 1Max-Planck-Institut für die Physik des Lichts, Institut für Optik, Information und Photonik, Universität Erlangen-Nürnberg, Günther-Scharowsky-Str. 1, Bau 24, 91058 Erlangen, Deutschland — 2Physics Department, Blackett Laboratory, Imperial College, London SW7 2BZ, United Kingdom
We demonstrate for the first time the feasibility of free space quantum key distribution with continuous variables under real atmospheric conditions [1]. More specifically, we transmit weak coherent polarization states over a 100m free space channel on the roof of our institute’s building. In our scheme, signal and local oscillator are combined in a single spatial mode auto-compensating atmospheric fluctuations and resulting in excellent interference. Furthermore, the local oscillator acts as a spatial and a spectral filter thus allowing for unrestrained daylight operation.
[1] D. Elser et al., arXiv:0811.4756 [quant-ph] (2008).