Stimulated and Spontaneous Optical Generation of Electron Spin Coherence in Charged GaAs Quantum Dots

Dutt, Meenakshi; Cheng, Jun; Li, Bo; Xu, Xiaodong; Li, Xiaoqin; Berman, P. R.; Steel, Duncan G.; Bracker, A. S.; Gammon, D.; Economou, Sophia E.; Liu, Ren‐Bao; Sham, L. J.

doi:10.1103/physrevlett.94.227403

Cited by 265 publications

(205 citation statements)

References 55 publications

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“…39,40 More recently, this energy-level configuration has been achieved in semiconductor QDs. [41][42][43] The distance between the quantum dot and graphene can be changed by using the following methods: (a) by using a passive dielectric spacer between the quantum dot and graphene, (b) using quantum dots with different diameters, (c) by applying an external stress or strain fields to the system, and (d) by changing the concentration of quantum dots or graphene nanodisks.…”

Section: Theoretical Formalismmentioning

confidence: 99%

Dipole-dipole interaction between a quantum dot and a graphene nanodisk

et al. 2012

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We study theoretically the dipole-dipole interaction and energy transfer in a hybrid system consisting of a quantum dot and graphene nanodisk embedded in a nonlinear photonic crystal. In our model, a probe laser field is applied to measure the energy transfer between the quantum dot and graphene nanodisk, while a control field manipulates the energy transfer process. These fields create excitons in the quantum dot and surface plasmon polaritons in the graphene nanodisk which interact via the dipole-dipole interaction. Here, the nonlinear photonic crystal acts as a tunable photonic reservoir for the quantum dot, and is used to control the energy transfer. We have found that the spectrum of power absorption in the quantum dot has two peaks due to the creation of two dressed excitons in the presence of the dipole-dipole interaction. The energy transfer rate spectrum of the graphene nanodisk also has two peaks due to the absorption of these two dressed excitons. Additionally, energy transfer between the quantum dot and the graphene nanodisk can be switched on and off by applying a pump laser to the photonic crystal or by adjusting the strength of the dipole-dipole interaction. We show that the intensity and frequencies of the peaks in the energy transfer rate spectra can be modified by changing the number of graphene monolayers in the nanodisk or the separation between the quantum dot and graphene. Our results agree with existing experiments on a qualitative basis. The principle of our system can be employed to fabricate nanobiosensors, optical nanoswitches, and energy transfer devices.

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Section: Theoretical Formalismmentioning

confidence: 99%

Dipole-dipole interaction between a quantum dot and a graphene nanodisk

et al. 2012

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“…1, we choose X X ± and T − to form a three-level lambda system. Since the hole g-factor is nonzero in InAs self-assembled QDs, the optical transitions with orthogonal polarizations from a trion state to the spin ground states are non-degenerate, thus suppressing the spontaneously generated coherence which was observed in GaAs interface fluctuation QDs [4].…”

mentioning

confidence: 99%

“…The usual method of creating electron spin coherence in QDs is to use pulsed lasers [4][5][6]. Here, the demonstration of CPT by measurement of the absorption spectrum is evidence of the creation of electron spin coherence at a single QD level by continuous wave (CW) lasers.…”

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confidence: 99%

Coherent population trapping of an electron spin in a single negatively charged quantum dot

et al. 2008

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“…We analyze the squeezing spectrum S a (ω, θ) calculated using Eq. (20) for the case of strong driving fields (Ω 1 , Ω 2 , Ω 3 ≫ γ, γ 3 ) [26]. In the calculations, we assume e 2iωar/c = 1 and scale the spectrum in units of µ 2 f (r) 2 /(πγ 3 ).…”

Section: A Squeezing Spectrum: S a (ω θ)mentioning

confidence: 99%

“…However, in real atomic systems, it is difficult to meet this condition. Different schemes were later proposed to bypass the condition of non-orthogonal dipole moments [19][20][21]. Experimentally, coherence between the ground states arising from spontaneous emissions has been reported using electron spin polarization states in quantum dots [20] and zeeman sublevels in atomic systems [21].…”

Section: Introductionmentioning

confidence: 99%

Interference-assisted squeezing in fluorescence radiation

Arun

2013

Physics Letters A

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The squeezing spectrum of the resonance fluorescence is studied for a coherently driven four-level atom in the Y-type configuration. It is found that the squeezing properties of the fluorescence radiation are modified significantly when quantum interference of the spontaneous decays channels is included. We show a considerable enhancement of steady-state squeezing in spectral components for strong and off-resonant driving fields. The squeezing may be increased in both the inner and outer sidebands of the spectrum depending upon the choice of parameters. We also show that the interference can degrade the spectral squeezing by increasing the decay rates of atomic transitions. An analytical description using dressed states is provided to explain the numerical results.

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Stimulated and Spontaneous Optical Generation of Electron Spin Coherence in Charged GaAs Quantum Dots

Cited by 265 publications

References 55 publications

Dipole-dipole interaction between a quantum dot and a graphene nanodisk

Dipole-dipole interaction between a quantum dot and a graphene nanodisk

Coherent population trapping of an electron spin in a single negatively charged quantum dot

Interference-assisted squeezing in fluorescence radiation

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