Optique des états collectifs et des spins (OECS)
Domaines de Recherche
L’équipe "Optique des états collectifs et des spins (OECS)", conjointement avec l’équipe "Nanostructures Quantiques Propriétés Optiques (NQPO)"), développe son activité autour de 6 thèmes présentés dans la rubrique de l’axe PEPS, en s’appuyant sur les plateformes expérimentales de l’axe PEPS.
Nous rejoindre
Plusieurs possibilités de stages, thèses et post-doctorats sont offertes au sein des équipes, parmi lesquelles :
10 Membres
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Dernières publications
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Time-resolved photoluminescence investigation of (Mg, Zn) O alloy growth on a non-polar plane 
Auteur(s): Ali Mohammed jassim mohammed, Chauveau J. m., Bretagnon T.
(Article) Publié:
Superlattices And Microstructures, vol. 116 p.105-113 (2018)
Ref HAL: hal-01827268_v1
DOI: 10.1016/j.spmi.2018.02.001
Exporter : BibTex | endNote
Résumé: Excitons recombination dynamics in ZnMgO alloy have been studied by time-resolved photoluminescence according to temperature. At low temperature, localization effects of the exciton are found to play a significant role. The photoluminescence (PL) decays are bi-exponential. The short lifetime has a constant value, whereas the long lifetime shows a dependency with temperature. For temperature higher than 100 K the declines show an mono-exponential decay. The PL declines are dominated by non-radiative process at temperatures above 150 K. The PL lifetime dependancy with temperature is analysed using a model including localisation effects and non-radiative recombinations.
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Spin-lattice relaxation of optically polarized nuclei in p-type GaAs
Auteur(s): Kotur M., Dzhioev R. i., Vladimirova M., Cherbunin R. v., Sokolov P. s., Yakovlev D. r., Bayer M., Suter D., Kavokin K. v.
(Article) Publié:
Physical Review B, vol. 97 p.165206 (2018)
Texte intégral en Openaccess : 
Ref HAL: hal-01804765_v1
DOI: 10.1103/PhysRevB.97.165206
Exporter : BibTex | endNote
Résumé: Spin-lattice relaxation of the nuclear spin system in p-type GaAs is studied using a three-stage experimental protocol including optical pumping and measuring the difference of the nuclear spin polarization before and after a dark interval of variable length. This method allows us to measure the spin-lattice relaxation time T1 of optically pumped nuclei “in the dark,” that is, in the absence of illumination. The measured T1 values fall into the subsecond time range, being three orders of magnitude shorter than in earlier studied n-type GaAs. The drastic difference is further emphasized by magnetic-field and temperature dependencies of T1 in p-GaAs, showing no similarity to those in n-GaAs. This unexpected behavior finds its explanation in the spatial selectivity of the optical pumping in p-GaAs, that is only efficient in the vicinity of shallow donors, together with the quadrupole relaxation of nuclear spins, which is induced by electric fields within closely spaced donor-acceptor pairs. The developed theoretical model explains the whole set of experimental results.
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Spin temperature concept verified by optical magnetometry of nuclear spins
Auteur(s): Vladimirova M., Cronenberger S., Scalbert D., Ryzhov I. i., Zapasskii V. s., Kozlov G. g., Lemaitre A., Kavokin K. v.
(Article) Publié:
Physical Review B, vol. 97 p.041301 (2018)
Texte intégral en Openaccess :
DOI: 10.1103/PhysRevB.97.041301
Résumé: We develop a method of nonperturbative optical control over adiabatic remagnetization of the nuclear spin system and apply it to verify the spin temperature concept in GaAs microcavities. The nuclear spin system is shown to exactly follow the predictions of the spin temperature theory, despite the quadrupole interaction that was earlier reported to disrupt nuclear spin thermalization. These findings open a way for the deep cooling of nuclear spins in semiconductor structures, with the prospect of realizing nuclear spin-ordered states for high-fidelity spin-photon interfaces.
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