Delayed-choice test of complementarity with single photons

Vincent Jacques (1) , E. Wu (1, 2) , Frédéric Grosshans (1) , François Treussart (1) , Philippe Grangier (3) , Alain Aspect (4) , Jean-François Roch (1)

1 LPQM - Laboratoire de Photonique Quantique et Moléculaire
2 Key Laboratory of Optical and Magnetic Resonance Spectroscopy
3 Laboratoire Charles Fabry de l'Institut d'Optique / Optique quantique
4 laboratoire Charles Fabry de l'Institut d'Optique / Optique atomique

We report an experimental test of complementarity using clock-triggered single-photon pulses emitted by an individual N-V color center in a diamond nanocrystal. The single photons are sent into a Mach-Zehnder interferometer with an output beamsplitter of adjustable reflection coefficient R. In addition, the choice of introducing or removing this beamsplitter is random and relativistically space-like separated from the entering of the photon inside the interferometer, as required for the Wheeler's delayed-choice regime. Each set value of R allows us to observe interference with visibility V and to obtain incomplete which-path information characterized by the distinguishability D. The measured values of V and D are found to obey the complementarity relation V²+D²=<1.

Domaines: Physique Quantique [quant-ph]

Vincent Jacques, E. Wu, Frédéric Grosshans, François Treussart, Philippe Grangier, et al.. Delayed-choice test of complementarity with single photons. Physical Review Letters, 2008, 100 (22), pp.220402. ⟨10.1103/PhysRevLett.100.220402⟩. ⟨hal-00202608⟩