Darmstadt 2008 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe

Q: Fachverband Quantenoptik und Photonik

Q 61: Quanteninformation (Photonen und nichtklassisches Licht II)

Q 61.3: Vortrag

Freitag, 14. März 2008, 14:30–14:45, 1A

Modal Properties of Parametric Down-conversion in the High Gain Regime — •Kaisa Laiho, Malte Avenhaus, and Christine Silberhorn — Max Planck Junior Research Group, Günther-Scharowsky-Str. 1 / Bau 24, D-91058 Erlangen

Parametric down-conversion (PDC) is widely used in the low gain regime as a source of photon pairs. It is also a promising candidate for Non-Gaussian state engineering [1]. Recently, bright waveguided PDC sources have become available. In this high gain regime it is possible to generate pairs of pairs, which can be understood as quadrature squeezing in the continuous variable picture.

The photon pairs generated in the PDC process are spectrally correlated. Although we use a broadband, ultrafast pump, the phasematching is a limiting factor. In order to be able to define the state as a broadband single mode squeezer, it needs to be decorrelated [2]. We have studied the spectral correlations in the ultrafast regime for a 10mm long type II PP-KTP waveguide and spectrally resolved the tilted correlation function. Our measured photon statistics indicate strong multimodal behaviour. To modify the spectral correlations we have cut down the waveguide to 2.5mm length and study the modal properties by spectral filtering. Ultimately, we aim at Non-Gaussian state preparation where it is crucial to drive the state towards single mode characteristics to ensure the purity.

[1] A. I. Lvovsky et al., Phys. Rev. Lett. 87, 050402 (2001)

[2] P. P. Rohde et al., New J. Phys. 9, 91 (2007)