"Experimental Confirmation of the Fundamental Principle of Wave-Particle Duality"
Figure 1. Double-path single-photon interferometer with controllable source purity used in our ENBS model.
Two SPDC crystals, PPLN1 and PPLN2, are pumped and seeded
simultaneously by the same pump and seed coherent lasers, respectively,
resulting in the emission of two signal photons s1 or s2 for quantum
interference detection at PD. Then, conjugate idler photons i1 and i2
provide the which-path (or which-source) information, where the
controllable source purity is determined by the overlap between the
SPACS of one of the idler modes and the unchanged coherent state of
another idler mode. Two idler fields can be detected independently by
detectors DA and DB. Credit: Institute for Basic Science
