Stuttgart 2012 – wissenschaftliches Programm
Q 69.8: Vortrag
Freitag, 16. März 2012, 15:45–16:00, V38.04
Parametric frequency down-conversion of single photons — •Susanne Blum1, Georgina Olivares-Rentería2,3, Carlo Ottaviani3, Sebastian Zaske1, Andreas Lenhard1, Christoph Becher1, and Giovanna Morigi1 — 1Universität des Saarlandes, Germany — 2Universidad de Concepción, Chile — 3Universitat Autònoma de Barcelona, Spain
Efficient single photon transmission in future quantum networks requires wavelengthes in the low loss band of optical fibres. Currently most single photon sources do not emit in this spectral region, but rather in the red or near-infrared. We analyse theoretically the conversion efficiency of single photons into the low-loss band at 1550 nm, using difference frequency generation in a χ(2) material. For this purpose we use Heisenberg-Langevin equations for the signal, idler, and pump fields, in the limit of a strong classical signal field. We consider the effects of quantum noise sources, e.g. photon loss in pump and ilder modes, and noise photon generation at 1550 nm due to optical parametric fluorescence as well as stokes and antistokes scattering from the signal to idler wavelength. Using this model we study the single photon down-conversion process by calculating the intensity-intensity correlationfunction , the influence of quantum noise sources and signal to noise ratios at gated detectors. Our analysis shows that values of g(2)(0) far below 0.5 can be achieved in present experiments . We discuss in gereral the bounds on the level of noise for realising efficient single-photon down-conversion for quantum communication purposes.
 S. Zaske et al., Optics Express, 19, 12825 (2011)