Non‐Blinking Single‐Photon Generation with Anisotropic Colloidal Nanocrystals: Towards Room‐Temperature, Efficient, Colloidal Quantum Sources

Blinking and single-photon emission can be tailored in CdSe/CdS core/shell colloidal dot-in-rods. By increasing the shell thickness it is possible to obtain almost non-blinking nanocrystals, while the shell length can be used to control single-photon emission probability

Interaction hyperfine spin du trou-spin des noyaux dans les boites quantiques d InAs/GaAs

PARIS-BIUSJ-Physique recherche (751052113) / SudocSudocFranceF

Three-dimensional THz lumped-circuit resonators

International audienceOur work describes a novel three dimensional meta-material resonator design for optoelectronic applications in the THz spectral range. In our resonant circuits, the capacitors are formed by double-metal regions cladding a dielectric core. Unlike conventional planar metamaterials, the electric field is perpendicular to the surface and totally confined in the dielectric core. Furthermore, the magnetic field, confined in the inductive part, is parallel to the electric field, ruling out coupling through propagation effects. Our geometry thus combines the benefit of double-metal structures that provide parallel plate capacitors, while maintaining the ability of meta-material resonators to adjust independently the capacitive and inductive parts. Furthermore, in our geometry, a constant bias can be applied across the dielectric, making these resonators very suitable for applications such as ultra-low dark current THz quantum detectors and amplifiers based on quantum cascade gain medium

Two-phonon process and hyperfine interaction limiting slow hole-spin relaxation time in InAs/GaAs quantum dots

International audienceWe study the hole-spin relaxation in p-doped InAs quantum dots. Two relaxation mechanisms are evidenced, at low magnetic field (0≤B≤2T) and low temperature (2≤T≤50K), by using a pump-probe configuration and a recent experimental technique working in the frequency domain. At T=2K, the coupling to nuclear spins and the hole wave-function inhomogeneity fix the hole-spin relaxation rate value, Γ1h≈1μs-1. It decreases with increasing magnetic field and reaches a plateau at 0.4 μs-1. At T≥7K, two-phonon spin-orbit process dominates and leads to a quadratic temperature dependence of Γ1h, in good agreement with theory

Experimental Evidence of the Hyperfine Interaction between Hole and Nuclear Spins in InAs/GaAs Quantum Dots

AbstractThe spin dynamics of resident holes in singly p-doped InAs/GaAs quantum dots is studied by pump-probe photo-induced circular dichroism experiments. We show that the hole spin dephasing is controlled by the hyperfine interaction between the hole spin and nuclear spins. We find a characteristic hole spin dephasing time of 12 ns, in close agreement with our calculations based on a dipole-dipole coupling between the hole and the quantum dot nuclei. Finally we demonstrate that a small external magnetic field, typically 10 mT, quenches the hyperfine hole spin dephasing.</jats:p

Hole-Nuclear Spin Interaction in Quantum Dots

International audienceWe have measured the carrier spin dynamics in p-doped InAs/GaAs quantum dots by pump-probe and time-resolved photoluminescence experiments. We obtained experimental evidence of the hyperfine interaction between hole and nuclear spins. In the absence of an external magnetic field, our calculations based on dipole-dipole coupling between the hole and the quantum dot nuclei lead to a hole-spin dephasing time for an ensemble of dots of 14 ns, in close agreement with experiments

Experimental evidence of the hyperfine interaction between hole and nuclear spins in InAs/GaAs quantum dots

Symposium on Novel Materials and Devices for Spintronics, San Francisco, CA, APR 14-17, 2009International audienceThe spin dynamics of resident holes in singly p doped InAs/GaAs quantum dots is studied by pump probe photo-induced circular dichroism experiments We show that the hole spin dephasing is controlled by the hyperfine interaction between the hole spin and nuclear spins We find a characteristic hole spin dephasing time of 12 ns, in close agreement with our calculations based on a dipole-dipole coupling between the hole and the quantum dot nuclei Finally we demonstrate that a small external magnetic field typically 10 mT quenches the hyperfine hole spin dephasin

Single-Photon Sources: Non-Blinking Single-Photon Generation with Anisotropic Colloidal Nanocrystals: Towards Room-Temperature, Efficient, Colloidal Quantum Sources (Adv. Mater. 14/2013)

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