Abstract
The photoluminescence of a single nickel–nitrogen NE8 color center in a diamond nanocrystal is investigated at room temperature under pulsed excitation by scanning confocal optical microscopy. Photon arrival times are analyzed in terms of the temporal intensity correlation function. Antibunching at short times and bunching behavior for longer times is observed, associated with sub- and super-Poissonian statistics, respectively. The behavior is interpreted by a ‘on–off’ state model, and transition rates between these two states are inferred from intensity correlation measurements realized at different excitation powers. NE8 color center photoluminescence quantum yield is evaluated to be 65%, a value higher than achieved for a nitrogen-vacancy color center, which is, up to now, the most practical single emitter to build a reliable single-photon source at room temperature.
Acknowledgements
We thank Patrick Georges for the loan of the cw Ti:Sapphire laser and we acknowledge the help of Vincent Jacques and Gérard Roger. This work was supported by the ‘EQUIND’ and the ‘Nano4Drugs’ projects funded by European Commission (FP6 project numbers IST-034368 and LSHB-CT-2005-019102), the ‘PROSPIQ’ project funded by Agence Nationale de la Recherche, C'Nano Ile-de-France and the Australian Research Council Discovery Projects Scheme. E. Wu acknowledges financial support from EADS and the Graduate School of East China Normal University and H. Zeng thanks Programme Hubert Curien of Ministére des Affaires étrangères, National Natural Science Fund (Grant No. 1077404) and National Key Project for Basic Research (Grant No. 2006CB921105).