Fourier-transform magnetophotoluminescence spectroscopy of donor-bound excitons in GaAs

Karasyuk, V. A.; Beckett, Daniel; Nissen, M. K.; Villemaire, André; Steiner, T.; Thewalt, M. L. W.

doi:10.1103/physrevb.49.16381

Cited by 44 publications

(39 citation statements)

References 24 publications

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“…This assumption is reasonable: as the barrier becomes thicker, the sign of h 0 should tend toward the g factor for holes in bulk GaAs, which is known to be positive [13,14]. Because h 0 remains positive, it is a change of sign of t in Eq.…”

Section: (C)mentioning

confidence: 99%

Antibonding Ground States in InAs Quantum-Dot Molecules

Climente²,

et al. 2009

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Antibonding ground states in InAs quantum-dot moleculesCoherent tunneling between two InAs quantum dots forms delocalized molecular states. Using magnetophotoluminescence spectroscopy we show that when holes tunnel through a thin barrier, the lowest energy molecular state has bonding orbital character. However, as the thickness of the barrier increases, the molecular ground state changes character from a bonding orbital to an antibonding orbital, confirming recent theoretical predictions. We explain how the spin-orbit interaction causes this counterintuitive reversal by using a four-band k Á p model and atomistic calculations that account for strain.

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Section: (C)mentioning

confidence: 99%

Antibonding Ground States in InAs Quantum-Dot Molecules

Climente²,

et al. 2009

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“…The optical transitions A and A * are to the lowest en- ergy level of the D 0 X system (state |e , well separated from the next level |e ′ ), which has two electrons in a singlet state and a spin-down hole with m h = − 1 2 localized at the donor site 13 . The optical selection rules of this system have been characterized very well 26 and show a strong polarization dependence. For the D 0 system, H-polarized light couples to the A * transition (with a change in angular momentum ofh) but not to the A transition.…”

Section: A Polarization Puritymentioning

confidence: 99%

“…To study the coherent properties of such ensembles we first find the spectral position of the relevant optical transitions 29 with photoluminescence and transmission spectroscopy. We then resolve the fine spectra of the Zeeman-split levels 26 with the pump-assisted transmission spectroscopy. After identifying the D 0 -D 0 X system in this manner, we could demonstrate electromagnetically induced transparency 30 (EIT) with this medium, which is a quantum optical effect that uses the D 0 spin coherence.…”

Section: Application: Spectroscopy and Eit With N-gaasmentioning

confidence: 99%

Polarization-preserving confocal microscope for optical experiments in a dilution refrigerator with high magnetic field

Sladkov

Bakker

Chaubal

et al. 2011

Review of Scientific Instruments

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We present the design and operation of a fiber-based cryogenic confocal microscope. It is designed as a compact cold-finger that fits inside the bore of a superconducting magnet, and which is a modular unit that can be easily swapped between use in a dilution refrigerator and other cryostats. We aimed at application in quantum optical experiments with electron spins in semiconductors and the design has been optimized for driving with, and detection of optical fields with well-defined polarizations. This was implemented with optical access via a polarization maintaining fiber together with Voigt geometry at the cold finger, which circumvents Faraday rotations in the optical components in high magnetic fields. Our unit is versatile for use in experiments that measure photoluminescence, reflection, or transmission, as we demonstrate with a quantum optical experiment with an ensemble of donor-bound electrons in a thin GaAs film.

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“…This inhomogeneity necessitates the use of spin-echo techniques to synchronize each qubit with the master clock. This technical burden may be relieved by using donor-bound excitons instead, as these impurity transitions form the needed Λ transition but show improved g homogeneity [27,28].…”

mentioning

confidence: 99%

Quantum Computers Based on Electron Spins Controlled by Ultrafast Off-Resonant Single Optical Pulses

Clark

Ladd

et al. 2007

Phys. Rev. Lett.

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We describe a fast quantum computer based on optically controlled electron spins in charged quantum dots that are coupled to microcavities. This scheme uses broad-band optical pulses to rotate electron spins and provide the clock signal to the system. Non-local two-qubit gates are performed by phase shifts induced by electron spins on laser pulses propagating along a shared waveguide. Numerical simulations of this scheme demonstrate high-fidelity single-qubit and twoqubit gates with operation times comparable to the inverse Zeeman frequency.PACS numbers: 03.67. Lx, 32.80.Qk, 33.35.+r, 42.65.Re Quantum computers potentially allow improvement in computational speed over existing computers if an architecture is found with a fast clock rate and the ability to be scaled to many qubits and operations [1]. Electron spins of charged semiconductor quantum dots are promising candidates for such an architecture because of their potential integration into existing microtechnology. Most proposals for electron spin quantum computers [2,3,4,5], however, restrict logic operations to nearest-neighbors, limiting the computational clock rate. Optically mediated quantum logic [6,7,8,9] for two-qubit gates and fast single qubit rotations [10,11] may improve the overall clock rate of the system. Several previous works suggest techniques for fast single-qubit rotations of electron spins. Ground-state coherence generation via ultrafast pulses in molecular, atomic, and quantum dot spectroscopy [11,12,13,14,15,16] indicates the ability to control ground state populations and phases. This control is faster than that of microwave pulses or multiple, adiabatic narrow-band optical pulses. The application of ultrafast pulses to U(1) control of single quantum-dot qubits has been proposed [10]. Here we describe complete optical SU(2) control of single dots using similar techniques.There are also proposals for optically-mediated entanglement formation between two non-local qubits. One type of proposal uses coherently generated single photons [9,17], but requires precisely shaped optical pulses. Recent methods for the entanglement of atomic ensembles via simple optical pulses [18,19] have led to proposals for optically-mediated two-qubit gates based on small phase shifts of light via single qubits in cavities [8]. These latter techniques may be easier and faster than the use of coherently generated single photons. Here, we propose a unique way to combine both fast, SU(2) single-qubit rotations and fast, optically-mediated two-qubit gates on a single semiconductor chip. These elements may lead toward the fastest potentially-scalable quantum computing scheme of which the authors are aware. tecture. It is a square millimeter of a semiconductor chip patterned with cavities. Each cavity holds a single charged quantum dot and is connected to other cavities through a switched, circular waveguide. Each quantum dot can be individually addressed by focused optical pulses incident perpendicular to the plane of the chip to perform single qubit rotations. ...

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Fourier-transform magnetophotoluminescence spectroscopy of donor-bound excitons in GaAs

Cited by 44 publications

References 24 publications

Antibonding Ground States in InAs Quantum-Dot Molecules

Antibonding Ground States in InAs Quantum-Dot Molecules

Polarization-preserving confocal microscope for optical experiments in a dilution refrigerator with high magnetic field

Quantum Computers Based on Electron Spins Controlled by Ultrafast Off-Resonant Single Optical Pulses

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