We propose a method to study and characterize the spatial and temporal properties of degenerate photon pairs emitted in SPDC, using a filtering system combined with temperature variation of the nonlinear crystal. The photons can be distinguished. We relate these to the measured Hong-Ou-Mandel interference dip of the photons, measured in a parallel experiment. The theoretical plots match very well with the experimental results.
Matteo Galli, Marco Clementi, Thanavorn Poempool