Postselected versus nonpostselected quantum teleportation using parametric down-conversion

We study the experimental realization of quantum teleportation as performed by Bouwmeester et al. [Nature (London) 390, 575 (1997)] and the adjustments to it suggested by Braunstein and Kimble [Nature (London) 394, 841 (1998)]. These suggestions include the employment of a detector cascade and a relative slow-down of one of the two down-converters. We show that coincidences between photon pairs from parametric down-conversion automatically probe the non-Poissonian structure of these sources. Furthermore, we find that detector cascading is of limited use, and that modifying the relative strengths of the down-conversion efficiencies will increase the time of the experiment to the order of weeks. Our analysis therefore points to the benefits of single-photon detectors in non post selected-type experiments, a technology currently requiring roughly 6 degrees K operating conditions.