Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Applied Physics Letters

Internal and external polarization memory loss in single semiconductor quantum dots

Qu‐Quan Wang, Andreas Müller, Pablo Bianucci, Chih-Kang Ken Shih, Mu-Tian Cheng, Huijun Zhou, Jiashuo Han

Published Oct 2, 2006• 7 citations
Publisher

Abstract

By using nonlinear resonant optical control and polarized photoluminescence, the authors studied the intensity dependence of exciton spin relaxation and photoluminescence polarization in single self-assembled InGaAs quantum dots. Data from dots with different dipole moments reveal two distinctive channels for polarization memory loss: (i) an external pathway due to carrier escape and capture to and from the wetting layer that is responsible for memory loss increasing with intensity and (ii) an internal loss channel due to intrinsic spin relaxation. The values obtained rule out a universal freezing of exciton spin relaxation in single self-assembled quantum dots related to the wetting layer.

DOI
10.1063/1.2360202

Related papers

Internal and external polarization memory loss in single quantum dots

Qu‐Quan Wang, Andreas Müller, Mu-Tian Cheng +3 more

We study exciton spin relaxation in single semiconductor quantum dots using non-linear resonant optical control. Experiments reveal two distinct channels for spin relaxation, external and internal, ruling out universal freezing of exciton spin relaxation.

Bulletin of the American Physical Society•Mar 16, 2006•0 citations

Internal and external polarization memory loss in single quantum dots

Qu‐Quan Wang, Andreas Müller, Mu-Tian Cheng +3 more

We study exciton spin relaxation in single semiconductor quantum dots using non-linear resonant optical control. Experiments reveal two distinct channels for spin relaxation, external and internal, ruling out universal freezing of exciton spin relaxation.

Conference on Lasers and Electro-Optics•Jan 1, 2006•0 citations

Polarization-dependent Rabi oscillations in single InGaAs quantum dots

Lucien Besombes, Jeremy J. Baumberg, Junichi Motohisa

Measurements of optical Rabi oscillations in the excited states of individual InGaAs are presented. Under pulsed resonant excitation we observe Rabi oscillations with increasing pulse area, which are damped after the first maximum and minimum. We show that the observed damping comes from an additional non-resonant generation of carriers in the quantum dot. The observation of Rabi oscillations provides an efficient way of directly measuring the excitonic transitions' dipole moments. A polarization anisotropy of the dipole moment is resolved in some of the quantum dots.

Semiconductor Science and Technology•Mar 3, 2004•7 citations

Efficiency of spin injection in novel InAs quantum dot structures: exciton vs. free carrier injection

Jan Beyer, I. A. Buyanova, Suwaree Suraprapapich +2 more

Unambiguous experimental evidence for a significant difference in efficiency of excitonic vs. free carrier spin injection is provided in novel laterally arranged self-assembled InAs/GaAs quantum dot structures, from optical orientation and tunable laser spectroscopy. A lower efficiency of exciton spin injection as compared to free carrier spin injection from wetting layers into QDs results in a distinct feature in luminescence polarization of the QDs as a function of excitation photon energy. It is shown that this difference is not related to carrier density and state-filling effects arising from the difference in optical absorption efficiency between the excitons and free carriers. Rather, it is a genuine property for exciton spin injection that suffers stronger spin relaxation due to Coulomb exchange interaction.

Journal of Physics Conference Series•Sep 1, 2010•6 citations

Optical spin polarization in negatively charged InAs self‐assembled quantum dots under applied electric field

Vladimir K. Kalevich, Michio Ikezawa, Tsuyoshi Okuno +5 more

Abstract We have studied the influence of an external electric field on the optical spin polarization of initially negatively charged InAs/GaAs quantum dots (QDs). The spin polarization of the carriers was controlled by measuring the photoluminescence (PL) circular polarization. We have found that the PL polarization of the QD is negative under an excitation above the GaAs barrier, and that it becomes positive under an excitation below the barrier. An applied negative electric field destroys both positive and negative polariza‐tion. The time decay of the negative polarization was found from time‐resolved measurements to exceed strongly the QD radiative lifetime. This fact indicates a long‐living spin memory in the dots under study.

physica status solidi (b)•Jun 25, 2003•10 citations

Exciton spin relaxation in InAs/InGaAlAs/InP(001) quantum dashes emitting near 1.55μm

M. Syperek, Łukasz Dusanowski, Michał Gawełczyk +5 more

Exciton spin and related optical polarization in self-assembled InAs/In0.53Ga0.23Al0.24As/InP(001) quantum dashes emitting at 1.55 μm are investigated by means of polarization- and time-resolved photoluminescence, as well as photoluminescence excitation spectroscopy, at cryogenic temperature. We investigate the influence of highly non-resonant and quasi-resonant optical spin pumping conditions on spin polarization and spin memory of the quantum dash ground state. We show that a spin pumping scheme, utilizing the longitudinal-optical-phonon-mediated coherent scattering process, can lead to the polarization degree above 50%. We discuss the role of intrinsic asymmetries in the quantum dash that influence values of the degree of polarization and its time evolution.

arXiv:1807.09143•Applied Physics Letters•Nov 7, 2016•11 citations
By using nonlinear resonant optical control and polarized photoluminescence, the authors studied the intensity dependence of exciton spin relaxation and photoluminescence polarization in single self-assembled InGaAs quantum dots. Data from dots with different dipole moments reveal two distinctive channels for polarization memory loss: (i) an external pathway due to carrier escape and capture to and from the wetting layer that is responsible for memory loss increasing with intensity and (ii) an internal loss channel due to intrinsic spin relaxation. The values obtained rule out a universal freezing of exciton spin relaxation in single self-assembled quantum dots related to the wetting layer.
Measurements of optical Rabi oscillations in the excited states of individual InGaAs are presented. Under pulsed resonant excitation we observe Rabi oscillations with increasing pulse area, which are damped after the first maximum and minimum. We show that the observed damping comes from an additional non-resonant generation of carriers in the quantum dot. The observation of Rabi oscillations provides an efficient way of directly measuring the excitonic transitions' dipole moments. A polarization anisotropy of the dipole moment is resolved in some of the quantum dots.
Unambiguous experimental evidence for a significant difference in efficiency of excitonic vs. free carrier spin injection is provided in novel laterally arranged self-assembled InAs/GaAs quantum dot structures, from optical orientation and tunable laser spectroscopy. A lower efficiency of exciton spin injection as compared to free carrier spin injection from wetting layers into QDs results in a distinct feature in luminescence polarization of the QDs as a function of excitation photon energy. It is shown that this difference is not related to carrier density and state-filling effects arising from the difference in optical absorption efficiency between the excitons and free carriers. Rather, it is a genuine property for exciton spin injection that suffers stronger spin relaxation due to Coulomb exchange interaction.
Abstract We have studied the influence of an external electric field on the optical spin polarization of initially negatively charged InAs/GaAs quantum dots (QDs). The spin polarization of the carriers was controlled by measuring the photoluminescence (PL) circular polarization. We have found that the PL polarization of the QD is negative under an excitation above the GaAs barrier, and that it becomes positive under an excitation below the barrier. An applied negative electric field destroys both positive and negative polariza‐tion. The time decay of the negative polarization was found from time‐resolved measurements to exceed strongly the QD radiative lifetime. This fact indicates a long‐living spin memory in the dots under study.
Exciton spin and related optical polarization in self-assembled InAs/In0.53Ga0.23Al0.24As/InP(001) quantum dashes emitting at 1.55 μm are investigated by means of polarization- and time-resolved photoluminescence, as well as photoluminescence excitation spectroscopy, at cryogenic temperature. We investigate the influence of highly non-resonant and quasi-resonant optical spin pumping conditions on spin polarization and spin memory of the quantum dash ground state. We show that a spin pumping scheme, utilizing the longitudinal-optical-phonon-mediated coherent scattering process, can lead to the polarization degree above 50%. We discuss the role of intrinsic asymmetries in the quantum dash that influence values of the degree of polarization and its time evolution.