Fig. 3: Time-energy entanglement.
From: Ultra-efficient generation of time-energy entangled photon pairs in an InGaP photonic crystal cavity
a–d Coincidence histograms after Tint = 1 s integration for different values of the phase acquired by the signal and idler photons in the interferometer φs + φi. The paths of the photons are shown in the first histogram (S short and L long). e, f Coincidence rate for the side peaks (green and red circles) and for the central peak (blue circles), respectively, as a function of φs + φi. The black curve is fitted with a sinusoidal function to extract the visibility of the fringes caused by two-photon interference. This measurement is obtained for P0 = 15 μW of pump power. Vertical error bars refer to the standard deviation of a Poisson distribution and horizontal ones to uncertainty on the photon pair phase.
