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Sub-picosecond ac spin current pulses are generated optically in GaAs bulk and quantum wells at room temperature and 90K through quantum interference between one-photon and two-photon absorptions driven by two phase-locked ultrafast laser…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 Brian A. Ruzicka , Karl Higley , Lalani K. Werake , Hui Zhao

Electron spin coherence has been generated optically in n-type modulation doped (In,Ga)As/GaAs quantum dots (QDs) which contain on average a single electron per dot. The coherence arises from resonant excitation of the QDs by…

We report theoretical and experimental studies of ambipolar spin diffusion in a semiconductor. A circularly polarized laser pulse is used to excite spin-polarized carriers in a GaAs multiple quantum well sample at 80 K. Diffusion of…

Mesoscale and Nanoscale Physics · Physics 2009-03-31 Hui Zhao , Matt Mower , G. Vignale

The electron spin dynamics in (111)-oriented GaAs/AlGaAs quantum wells is studied by timeresolved photoluminescence spectroscopy. By applying an external field of 50 kV/cm a two-order of magnitude increase of the spin relaxation time can be…

Materials Science · Physics 2015-05-28 A. Balocchi , Q. H. Duong , P. Renucci , B. Liu , C. Fontaine , T. Amand , D. Lagarde , X. Marie

Exciton, trion and electron spin dynamics in a 20 nm wide modulation-doped GaAs single quantum well are investigated using resonant ultrafast two-color Kerr rotation spectroscopy. Excitons and trions are selectively detected by resonant…

Mesoscale and Nanoscale Physics · Physics 2016-08-24 Sergiu Anghel , Akshay Singh , Felix Passmann , Hikaru Iwata , Nick Moore , Go Yusa , Xiaoqin Li , Markus Betz

Irradiating a semiconductor with circularly polarized light creates spin-polarized charge carriers. If the material contains atoms with non-zero nuclear spin, they interact with the electron spins via the hyperfine coupling. Here, we…

Mesoscale and Nanoscale Physics · Physics 2016-09-09 Raphael W. Mocek , Danil O. Tolmachev , Giovanni Cascio , Dieter Suter

Optical control of the spin coherence of quantum well electrons by short laser pulses with circular or linear polarization is studied experimentally and theoretically. For that purpose the coherent electron spin dynamics in a n-doped…

Mesoscale and Nanoscale Physics · Physics 2010-09-15 E. A. Zhukov , D. R. Yakovlev , M. M. Glazov , L. Fokina , G. Karczewski , T. Wojtowicz , J. Kossut , M. Bayer

Coherent interactions between spins in quantum dots are a key requirement for quantum gates. We have performed pump-probe experiments in which pulsed lasers emitting at different photon energies manipulate two distinct subsets of electron…

Mesoscale and Nanoscale Physics · Physics 2011-10-03 S. Spatzek , A. Greilich , Sophia E. Economou , A. Schwan , S. Varwig , D. R. Yakovlev , D. Reuter , A. D. Wieck , T. L. Reinecke , M. Bayer

Waveguide-based spin-photon interfaces on the GaAs platform have emerged as a promising system for a variety of quantum information applications directly integrated into planar photonic circuits. The coherent control of spin states in a…

The coupling of laser light to matter can exert sub-cycle coherent control over material properties, with optically induced currents and magnetism shown to be controllable on ultrafast femtosecond time scales. Here, by employing laser light…

Optics · Physics 2024-06-19 Q. Z. Li , S. Shallcross , J. K. Dewhurst , S. Sharma , P. Elliott

This study explores the relationship between spin diffusion, spin lifetime, electron density and lateral spatial confinement in two-dimensional electron gases hosted in GaAs quantum wells. Using time-resolved magneto-optical Kerr effect…

Mesoscale and Nanoscale Physics · Physics 2025-01-15 B. W. Grobecker , A. V. Poshakinskiy , S. Anghel , T. Mano , G. Yusa , M. Betz

We performed effective mass measurements employing microwave-induced resistance oscillation in a tunable-density GaAs/AlGaAs quantum well. Our main result is a clear observation of an effective mass increase with decreasing density, in…

Mesoscale and Nanoscale Physics · Physics 2017-09-01 X. Fu , Q. A. Ebner , Q. Shi , M. A. Zudov , Q. Qian , M. J. Manfra

The dynamic polarization of nuclear spins by photoexcited electrons is studied in a high quality GaAs/AlGaAs quantum well. We find a surprisingly high efficiency of the spin transfer from the electrons to the nuclei as reflected by a…

Mesoscale and Nanoscale Physics · Physics 2017-11-15 R. W. Mocek , V. L. Korenev , M. Bayer , M. Kotur , R. I. Dzhioev , D. O. Tolmachev , G. Cascio , K. V. Kavokin , D. Suter

Semiconductor microcavities offer unique means of controlling light-matter interactions, which have led to the development of a wide range of applications in optical communications and inspired proposals for quantum information processing…

Materials Science · Physics 2007-05-23 S. Ghosh , W. H. Wang , F. M. Mendoza , R. C. Myers , X. Li , N. Samarth , A. C. Gossard , D. D. Awschalom

We present a theory of the optical control of the spin of an electron in an InAs quantum dot. We show how two Raman-detuned laser pulses can be used to obtain arbitrary single-qubit rotations via the excitation of an intermediate trion…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 C. Emary , L. J. Sham

We investigate the spin-dependent dynamical response of a quantum ring with a spin-orbit interaction upon the application of linearly polarized, picosecond, asymmetric electromagnetic pulses. The oscillations of the generated dipole moment…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 Zhen-Gang Zhu , Jamal Berakdar

We demonstrate coherent optical control of a single hole spin confined to an InAs/GaAs quantum dot. A superposition of hole spin states is created by fast (10-100 ps) dissociation of a spin-polarized electron-hole pair. Full control of the…

Mesoscale and Nanoscale Physics · Physics 2012-01-09 T. M. Godden , J. H. Quilter , A. J. Ramsay , Yanwen Wu , P. Brereton , S. J. Boyle , I. J. Luxmoore , J. Puebla-Nunez , A. M. Fox , M. S. Skolnick

The coherent electron spin dynamics of an ensemble of singly charged (In,Ga)As/GaAs quantum dots in a transverse magnetic field is driven by periodic optical excitation at 1 GHz repetition frequency. Despite the strong inhomogeneity of the…

Mesoscale and Nanoscale Physics · Physics 2021-04-20 E. Evers , N. E. Kopteva , I. A. Yugova , D. R. Yakovlev , D. Reuter , A. D. Wieck , M. Bayer , A. Greilich

Electron spin dynamics is investigated in n-i-n GaAs/AlGaAs coupled quantum wells. The electron spin dephasing time is measured as a function of an external electrical bias under resonant excitation of the 1sHH intrawell exciton using a…

Mesoscale and Nanoscale Physics · Physics 2015-05-13 A. V. Larionov , L. E. Golub

We demonstrate methods to locally control the spin rotation of moving electrons in a GaAs channel. The Larmor frequency of optically-injected spins is modulated when the spins are dragged through a region of spin-polarized nuclei created at…

Mesoscale and Nanoscale Physics · Physics 2015-05-19 M. E. Nowakowski , G. D. Fuchs , S. Mack , N. Samarth , D. D. Awschalom
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