Generation of correlated photon pairs in type-II parametric down conversionrevisited

Type-II parametric down conversion in nonlinear optical crystals has turned out to be one of the most powerful methods to generate entangled photon pairs, and even allowed a large set of experiments on foundations of quantum mechanics and recent applications in quantum communication. In this paper, we present an experimental investigation of the emission characteristics for down-converted photons in order to investigate the possibility of high brightness sources for correlated photon pairs. Furthermore, we discuss possible ways to increase the collection efficiency for polarization entangled photon pairs.