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We have studied the coherent spin dynamics of excitons bound to acceptors, A0X, immersed in a CdTe quantum well by using time resolved photo-induced Faraday rotation. We have also measured the time-resolved differential transmission in... more
We have studied the coherent spin dynamics of excitons bound to acceptors, A0X, immersed in a CdTe quantum well by using time resolved photo-induced Faraday rotation. We have also measured the time-resolved differential transmission in order to determine a A0X lifetime of 220 ps, which is independent of the applied magnetic field. We show that at low magnetic field, the spin of A0X is completely frozen during a time, ≅ 4.5 ns, at least twenty times longer than its lifetime. We compare the spin properties of A0X with the spin properties of other charged excitons systems, and we conclude that the hyperfine interaction of the photo-created electron spin with nuclear spins is very likely to be at the origin of the observed spin dephasing times.
Research Interests: Engineering, Physics, Condensed Matter Physics, Applied Physics, Mathematical Sciences, and 12 morePhysical sciences, Coherence, SPIN, Dephasing, Exciton, Enseñanza - Aprendizaje Ciencias Naturales Y Exactas, óPtica, Hyperfine Structure, Faraday Effect, Ciencias Fisicas, Acceptor, and pump and probe
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Research Interests: Physics, Condensed Matter Physics, Magnetic field, Exciton Dynamics, Physical sciences, and 10 moreAstronomía, CHEMICAL SCIENCES, American physical society, Quantum Dot, Exciton, Enseñanza - Aprendizaje Ciencias Naturales Y Exactas, Quantum Point Contact, Ciencias Fisicas, Zeeman Effect, and Quantum Beats
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ABSTRACT We report on the precise determination of the electron Landé g factor and its anisotropy in self-assembled InAs/GaAs quantum dots (QDs), by means of measurements of Larmor precession frequencies in photoinduced circular dichroism... more
ABSTRACT We report on the precise determination of the electron Landé g factor and its anisotropy in self-assembled InAs/GaAs quantum dots (QDs), by means of measurements of Larmor precession frequencies in photoinduced circular dichroism (PCD) experiments performed with an oblique magnetic field. This optical technique, applied to an ensemble of QDs, is able to measure the electronic g factor corresponding to ground-state electrons resident in QDs emitting at a given energy of fundamental optical transition. In good agreement with recent theoretical results, we measure |g⊥|=0.397±0.003 and |g∥|=0.18±0.02 for QDs emitting at 1.32 eV.
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Research Interests: Physics, Condensed Matter Physics, III-V Semiconductors, Time Use, Magnetic field, and 15 morePhysical sciences, Spin Relaxation, CHEMICAL SCIENCES, Quantum Dot, Low Temperature, Dephasing, Time Domain, Spin Dynamics, Experimental Method, Hyperfine Structure, Frequency Domain, Spin Polarization, Power Density, Relaxation Time, and Circularly polarized
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Research Interests: Physics, Condensed Matter Physics, Hyperfine Interaction, Dynamic Nuclear Polarization, Magnetic field, and 15 morePhotoluminescence, Quantum Dots, Mathematical Sciences, Physical sciences, Excitons, Quantum Dot, Bistability, Low Temperature, Exciton, Optical Pumping, Energy Cost, Hyperfine Structure, Perturbation Theory, Spin Polarization, and GaAs
We use optical orientation technique to monitor the degeneracy control of exciton states in a single InAs∕GaAs quantum dot, achieved by applying an in-plane electric field. Under circularly polarized quasiresonant excitation, the exciton... more
We use optical orientation technique to monitor the degeneracy control of exciton states in a single InAs∕GaAs quantum dot, achieved by applying an in-plane electric field. Under circularly polarized quasiresonant excitation, the exciton photoluminescence shows a pronounced maximum of circular polarization at electric field corresponding to zero fine structure splitting. By analyzing the width of this maximum we are able to determine the homogeneous linewidth of the excitonic transition. This experimental method is shown to be very efficient to test and possibly tune the photonic properties of an individual quantum dot for the emission of entangled photon pairs.
Research Interests: Engineering, Physics, Materials Science, III-V Semiconductors, Photoluminescence, and 12 moreOptoelectronics, Semiconductor, Laser Linewidth, Physical sciences, Fine Structure Constant, Quantum Dot, Exciton, Electric Field, Experimental Method, Circular polarization, Quantum-Dot Laser, and Circularly polarized
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The spin interaction of a hole confined in a quantu m dot with the surrounding nuclei is described in terms of an effective magnetic field. We show that, in contrast to the Fermi contact hyperfine interaction for conduction electr ons,... more
The spin interaction of a hole confined in a quantu m dot with the surrounding nuclei is described in terms of an effective magnetic field. We show that, in contrast to the Fermi contact hyperfine interaction for conduction electr ons, the dipole-dipole hyperfine interaction is anisotropic for a hole, for both pure or mixed h ole states. We evaluate the
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ABSTRACT We report on the optical orientation of singly charged exciton X+ in a single self-assembled InAs/GaAs quantum dot. We show that the hyperfine interaction with the nuclei is responsible for a partial spin relaxation. This effect... more
ABSTRACT We report on the optical orientation of singly charged exciton X+ in a single self-assembled InAs/GaAs quantum dot. We show that the hyperfine interaction with the nuclei is responsible for a partial spin relaxation. This effect manifests only under modulated excitation polarization, while under steady optical pumping conditions, we measure a nuclear polarization large enough to screen its own fluctuations. This explains the high degree of circular polarization commonly reported for X+.
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ABSTRACT We report on electron spin manipulation in a single charge-tunable self-assembled InAs/GaAs quantum dot. The hyperfine interaction between the optically oriented electron and nuclear spins leads to the polarization of the quantum... more
ABSTRACT We report on electron spin manipulation in a single charge-tunable self-assembled InAs/GaAs quantum dot. The hyperfine interaction between the optically oriented electron and nuclear spins leads to the polarization of the quantum dot nuclei. The sign of the resulting Overhauser-shift depends on the trion state X+ or X- which demonstrates the transfer of spin polarization to the nuclei from the unpaired electron either in the initial state for X+, or in the final state for X-.
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ABSTRACT We present a detailed study of the hyperfine interaction between carrier and nuclear spins in InAs semiconductor quantum dots. Time resolved measurements on excitons in positively charged quantum dots show the electron spin... more
ABSTRACT We present a detailed study of the hyperfine interaction between carrier and nuclear spins in InAs semiconductor quantum dots. Time resolved measurements on excitons in positively charged quantum dots show the electron spin relaxation due to random fluctuations of the spin orientation of the nuclei in the quantum dot. A complimentary aspect of the hyperfine interaction can be uncovered in single dot continuous wave photoluminescence experiments in a weak magnetic field, namely the Overhauser shift due to the dynamic polarisation of the nuclei following excitation with circularly polarised light. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
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We model pump-probe experiments leading to the all-optical initialization of the hole spin of a p-doped InAs/GaAs quantum dots ensemble. We consider selection rules of mixed hole states and include periodic excitation conditions.... more
We model pump-probe experiments leading to the all-optical initialization of the hole spin of a p-doped InAs/GaAs quantum dots ensemble. We consider selection rules of mixed hole states and include periodic excitation conditions. Hyperfine interaction is taken into account as the common decoherence mechanism for the spins of electrons and holes. We show that the degree of hole spin polarization can be maximized by quenching the action of the hole hyperfine interaction with a small applied magnetic field. However additional hole spin relaxation mechanisms, in the microsecond time range, determine the absolute value of this maximum. Bibtex entry for this abstract Preferred format for this abstract (see Preferences) Find Similar Abstracts: Use: Authors Title Abstract Text Return: Query Results Return items starting with number Query Form Database: Astronomy Physics arXiv e-prints