Controlling two-particle conditional interference -: art. no. 023801

Conditional interference fringes are found when parametric down-converted photon pairs are sent to two Young's double slits. The transmitted photon pairs are detected in coincidence as a function of the transverse spatial coordinates. Conditional interference is found in the fourth-order interference pattern with and without second-order interference. A quantum multimode calculation shows that the fourth-order Young interference pattern is strongly dependent on the transverse profile of the pump laser that generates the twin photon pairs. Conditionality is observed by tailoring this profile. A control of the conditionality is obtained via the pump laser beam transverse profile.