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Habilitation à diriger des recherches

Lumière issue d'émetteurs individuels, applications.

Abstract : We experimentally studied properties of light emitted by single nano-particles. Our work was mainly devoted to fluorescence of single emitter used as a room temperature triggered single photon source for quantum cryptography. Such a source relies on the pulse excitation of a single emitter located at the focus of a high numerical aperture microscope objective. We showed evidence for non-classical light emission from a single dye molecule. Intensity noise was also studied by measuring Mandel parameter of the photon temporal distribution. At short integration time, we observed an intensity noise reduction from the single photon source, compared to an equivalent classical source. The measurement technique that we developed relies on a photon-by-photon timestamp acquisition, which furthermore allows one to infer molecular dynamical parameters. This technique appears as an alternative to usual time correlation measurement.
To overcome dye photobleaching, hardly compatible with applications, we replaced molecules by colour centres in diamond nanocrystals. Such a centre behave like a molecular emitter, and is furthermore perfectly photostable at room temperature. The triggered single photon source relying on the colour centre fluorescence was then used in a quantum key distribution setup in which photon propagate in free space. We showed experimentally that even in the presence of a strong attenuation on the transmission channel, the single photon source still allows two parties to share a secret, whereas attenuated laser pulses would not.
In this report, we also describe a few results on second-harmonic generation by single organic nanostructures. Analysis of such a signal is used as a diagnostic of the monocrystalline nature of the nano-ojects. Finally, we conclude by a brief overview of the new project that we just started concerning the coherent manipulation of the single spin in a diamond colour centre for quantum information processing.
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Habilitation à diriger des recherches
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https://tel.archives-ouvertes.fr/tel-00011177
Contributor : François Treussart <>
Submitted on : Friday, December 9, 2005 - 10:40:53 AM
Last modification on : Monday, February 15, 2021 - 10:47:16 AM
Long-term archiving on: : Friday, April 2, 2010 - 10:47:55 PM

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  • HAL Id : tel-00011177, version 1

Citation

François Treussart. Lumière issue d'émetteurs individuels, applications.. Physique [physics]. Université Pierre et Marie Curie - Paris VI, 2004. ⟨tel-00011177⟩

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