title: Delayed-choice test of quantum complementarity with interfering single photons.
abstract: We report an experimental test of quantum complementarity with single-photon pulses sent into a Mach-Zehnder interferometer with an output beam splitter of adjustable reflection coefficient R. In addition, the experiment is realized in Wheeler's delayed-choice regime. Each randomly set value of R allows us to observe interference with visibility V and to obtain incomplete which-path information characterized by the distinguishability parameter D. Measured values of V and D are found to fulfill the complementarity relation V2+D2 < or =1.
authors.affiliation: Laboratoire de Photonique Quantique et Moléculaire, Ecole Normale Supérieure de Cachan, UMR CNRS 8537, Cachan, France.
authors.forename: Vincent
authors.initials: V
authors.lastname: Jacques
authors.forename: E
authors.initials: E
authors.lastname: Wu
authors.forename: Frédéric
authors.initials: F
authors.lastname: Grosshans
authors.forename: François
authors.initials: F
authors.lastname: Treussart
authors.forename: Philippe
authors.initials: P
authors.lastname: Grangier
authors.forename: Alain
authors.initials: A
authors.lastname: Aspect
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Roch