Presented during my PhD defense at ICFO - The institute of Photonic Sciences. Barcelona (Spain), March 12 (2010) This talk shows that * The two-photon mode function, for photons generated in SPDC, can be written in a matrix form which is not as computational demanding as other ways to describe the downconverted state. * The internal correlations in the two-photon state can be suppress or enhance by tailoring the SPDC parameters. * The OAM content of the pump is completely transferred to the signal and idler photons, emitted all over a cone. It is only possible to introduce a selection rule that always holds if all possible emission directions are considered.
* The SPDC parameters and the detection system determine the portion of the cone that is detected in a noncollinear configuration, and therefore the amount of OAM that can be detected.
* The SPDC parameters and the detection system determine the portion of the cone that is detected in a noncollinear configuration, and therefore the amount of OAM that can be detected.