@article{HeuerMenzelMilonni2015,
  author    = {Heuer, Axel and Menzel, Ralf and Milonni, P. W.},
  title     = {Complementarity in biphoton generation with stimulated or induced coherence},
  series = {Physical review : A, Atomic, molecular, and optical physics},
  volume    = {92},
  journal   = {Physical review : A, Atomic, molecular, and optical physics},
  number    = {3},
  publisher = {American Physical Society},
  address   = {College Park},
  issn      = {1050-2947},
  doi       = {10.1103/PhysRevA.92.033834},
  pages     = {8},
  year      = {2015},
  abstract  = {Coherence can be induced or stimulated in parametric down-conversion using two or three crystals when, for example, the idler modes of the crystals are aligned. Previous experiments with induced coherence [Phys. Rev. Lett. 114, 053601 (2015)] focused on which-path information and the role of vacuum fields in realizing complementarity via reduced visibility in single-photon interference. Here we describe experiments comparing induced and stimulated coherence. Different single-photon interference experiments were performed by blocking one of the pump beams in a three-crystal setup. Each counted photon is emitted from one of two crystals and which-way information may or not be available, depending on the setup. Distinctly different results are obtained in the induced and stimulated cases, especially when a variable transmission filter is inserted between the crystals. A simplified theoretical model accounts for all the experimental results and is also used to address the question of whether the phases of the signal and idler fields in parametric down-conversion are correlated.},
  language  = {en}
}
@article{HeuerMenzelMilonni2015,
  author    = {Heuer, A. and Menzel, R. and Milonni, P. W.},
  title     = {Induced Coherence, Vacuum Fields, and Complementarity in Biphoton Generation},
  series = {Physical review letters},
  volume    = {114},
  journal   = {Physical review letters},
  number    = {5},
  publisher = {American Physical Society},
  address   = {College Park},
  issn      = {0031-9007},
  doi       = {10.1103/PhysRevLett.114.053601},
  pages     = {5},
  year      = {2015},
  abstract  = {It is well established that spontaneous parametric down-conversion with induced coherence across two coupled interferometers results in high-visibility single-photon interference. We describe experiments in which additional photon channels are introduced such that "which-path" information is made possible and the fringe visibility in single-photon interference is reduced in accordance with basic notions of complementarity. However, these additional pathways result in nearly perfect visibility when photons are counted in coincidence. A simplified theoretical model accounts for these observations and attributes them directly to the vacuum fields at the different crystals.},
  language  = {en}
}