Berlin 2005 – wissenschaftliches Programm

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Q: Quantenoptik und Photonik

Q 3: Poster Quanteninformation, -kommunikation und Quantencomputer

Q 3.16: Poster

Freitag, 4. März 2005, 11:00–12:30, Poster HU

Ultrashort-pulse pumped spontaneous parametric down-conversion for entangled photons — •Sebastian Bange, Martin Ostermeyer, and Ralf Menzel — University of Potsdam, Am Neuen Palais 10, 14469 Potsdam

During the last decade, the process of spontaneous parametric downconversion (SPDC) in non-centrosymmetric crystals has been proven to be a reliable source for pairs of entangled photons. In recent years, SPDC-pumping with ultrashort laser pulses in the pico- and femtosecond regime has attracted increasing attentention. The higher intensities allow for the generation of entangled multi-photon states as well as new imaging techniques based on the higher flux of entangled photons [1].

Envisaging experiments in the field of quantum information, we are presenting a setup for picosecond-pulse pumped SPDC. Careful engineering of the quantum state is critical for the fidelity of the entanglement especially when working with ultrashort pulses [2]. The special needs of compensation schemes for runtime differences in this regime are discussed. Furthermore the ramifications of the entanglement with regard to a broader bandwidth in the emission of the photons is considered.

[1] A. Gatti, E. Brambilla and L.A. Lugiato, Phys. Rev. Lett. 90(13) 133603 (2003)

[2] Y.-H. Kim and W. P. Grice, J. Mod. Opt 49(14/15) 2309 (2002)