Hannover 2010 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 66: Quantum Information: Photons and Nonclassical Light III

Q 66.8: Talk

Friday, March 12, 2010, 15:45–16:00, E 214

Diffraction at a blazed grating as a tool for characterizing the degree of spatial entanglement of different biphoton sources — •Dirk Puhlmann and Martin Ostermeyer — Universität Potsdam, Institut für Physik und Astronomie, Karl-Liebknecht-Str. 24-25, 14476 Potsdam, Germany

Correlations between photons are interesting for a number of applications and concepts in metrology, in particular for resolution improvements in different methods of quantum imaging. We demonstrate the application of a blazed grating for the characterization of the degree of spatial correlations of biphotons. For spatially correlated biphotons a new order of diffraction (OD) is observed in the far field distribution of the two photon rate behind the grating. This new OD appears at a far field angle, expected for single photons of half the original wavelength [1]. The higher the degree of spatial correlation of the biphotons, the stronger becomes this new OD. Thus the diffraction distribution behind the blazed grating can be used to characterize the spatial correlations of the biphotons. This characterization process is carried out for different biphoton sources, including spontaneous parametric down conversion in bulk crystals as well as in periodically poled MgO doped stoichiometric Lithium Tantalat (PP-MgO:SLT).

[1] M.Ostermeyer, D. Puhlmann, D. Korn, JOSA-B 26, 2347 (2009)