Phonon-assisted incoherent excitation of a quantum dot and its emission properties

Weiler, Stefanie; Ulhaq, Ata; Ulrich, S.; Richter, Daniel; Jetter, Michael; Michler, Peter; Roy, C.; Hughes, Stephen

doi:10.1103/physrevb.86.241304

Cited by 72 publications

(94 citation statements)

References 32 publications

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“…, where we choose a coupling strength of α = 0.06 ps 2 and a phonon bath frequency cut-off of ω b = 1 meV, both consistent with the experimentaltheory results of Weiler et al [27]. The polaron transform renormalizes the system Hamiltonian by coherently reducing the effective drive strength Ω(t) and introducing a Lamb-type shift in the exciton resonant frequency, but we have assumed that these effects can be absorbed into the original definitions of these parameters and neglected henceforth (such that H S = H S ).…”

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confidence: 68%

Spectral asymmetries in the resonance fluorescence of two-level systems under pulsed excitation

2018

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We present an open-system master equation study of the coherent and incoherent resonance fluorescence spectrum from a two-level quantum system under coherent pulsed excitation. Several pronounced features which differ from the fluorescence under a constant drive are highlighted, including a multi-peak structure and a pronounced off-resonant spectral asymmetry, in stark contrast to the conventional symmetrical Mollow triplet. We also study semiconductor quantum dot systems using a polaron master equation, and show how the key features of dynamic resonance fluorescence change with electron-acoustic-phonon coupling.The theory of resonant scattering of light from a twolevel system (TLS) is a major achievement in quantum optics and provides an experimentally accessible gateway to probing strong-field quantum optics. In recent decades, advances in the ability to coherently manipulate atomic systems with light has allowed for a breadth of technological innovations which harness the quantum mechanical properties of these systems [1]. Furthermore, quantum dots (QDs) -semiconductor materials confined in three dimensions, with excited electron-hole pairs (excitons) mimicking the behaviour of an excited atom, can serve as "artificial atoms", maintaining the physics of the quantized system's interaction with the electromagnetic field, but with tunable properties and potential for scalability [2]. Semiconductor QDs have been the subject of much recent research for their potential as sources of quantum light, particularly single and entangled photons [3]. While constant excitation with a continuous wave (cw) laser drive can be used to create a TLS singlephoton source, often technological proposals require a deterministic source -one that can be triggered on-demand. This is typically done by an optical pulse, which renders resonance fluorescence (RF) of a TLS a genuine timedependent quantum dynamical process.The usual features of the RF spectrum under strong cw excitation manifest as the so-called Mollow triplet [4], where the power spectrum of the scattered field takes on a characteristic three-peak resonance structure due to radiative transitions between eigenstates of the system Hamiltonian, as well as a delta function peak at the (monochromatic) drive frequency corresponding to coherent elastic scattering. However, under excitation by a short pulse, the RF spectrum can take on features which obscure or eliminate this characteristic spectrum, especially under off-resonant excitation. The pulsed RF spectrum has been studied theoretically in atomic systems [5][6][7][8][9][10], and more recently in QD-cavity systems for on-resonance excitation [11], where a dynamic spectrum has been observed in the presence of cavity coupling [12].In this Letter, we describe the unique features of pulsed * c.gustin@queensu.ca RF spectra in depth using a master equation approach, and explore the different effects under time-dependent excitation, which are of interest to emerging experimental studies of pulsed quantum optical systems. In particul...

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confidence: 68%

Spectral asymmetries in the resonance fluorescence of two-level systems under pulsed excitation

2018

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“…Since up to date only significantly smaller phonon assisted excitation rates are reported for cw excitation [41,44], we demonstrate in this section experimentally that the incoherent phonon assisted pump γ ph rates can exceed the radiative recombination rates γ X 0 →cgs of the neutral exciton state in a QD.…”

Section: Phonon Assisted Pump Ratesmentioning

confidence: 99%

“…Most importantly, the resulting charge carrier -phonon interaction spectrum J(∆ω) is highly sensitive to the energy detuning of the excitation laserhω L . Only for positive detunings ∆ω i→j = ω L −ω i→j > 0 of the excitation laser with respect to the optical transition i → j, the spectrum acquires considerable values since LA -phonons are frozen out at low temperatures and phonon emission processes dominate [40][41][42][43]. When the excitation laser resonantly drives cgs →→ 2X 0 , it is blue detuned from 2X 0 → X 0 (∆ω 2X→X 0 = +∆ b > 0) and red detuned from X 0 → cgs (∆ω 2X→X 0 = −∆ b < 0).…”

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confidence: 99%

“…For a blue detuning of the excitation laser of ∆ω 2X 0 →X 0 = ∆ b = +0.93 meV, the charge carrier LA-phonon interaction will lead to an incoherent population transfer from X 0 to 2X 0 via a phonon assisted excitation process [41] (inset on Fig.2c): It works effectively as an incoherent population pump-rate γ phonon from X 0 to 2X 0 . This pump rate γ phonon increases the steady state population of the biexciton n 2X 0 with respect to the exciton n X 0 .…”

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Optical control of nonlinearly dressed states in an individual quantum dot

et al. 2016

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We report two-photon resonance fluorescence of an individual semiconductor artificial atom. By non-linearly driving a single semiconductor quantum dot via a two-photon transition, we probe the linewidth of the two-photon processes and show that, similar to their single-photon counterparts, they are close to being Fourier limited at low temperatures. The evolution of the population of excitonic states with the Rabi frequency exhibits a clear s-shaped behavior, indicative of the nonlinear response via the two photon excitation process. We model the non-linear response using a 4-level atomic system representing the manifold of excitonic and biexcitonic states in the quantum dot and show that quantitative agreement is obtained only by including the interaction with LAphonons in the solid state environment. Finally, we demonstrate the formation of dressed states emerging from a two-photon interaction between the artificial atom and the excitation field. The non-linear optical dressing induces a mixing of all four excitonic states that facilitates the tuning of the polarization selection rules of the artificial atom.

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“…A number of different situations have been investigated [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15]. These include experimental studies of the effect of phonons on the Rabi oscillations, Autler-Townes splitting, and the Mollow triplet of the fluorescence field emitted by a driven quantum dot [16][17][18][19][20][21][22][23][24].…”

Section: Introductionmentioning

confidence: 99%

Engineering a squeezed phonon reservoir with a bichromatic driving of a quantum dot

Gao

Ficek

2016

Phys. Rev. A

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We demonstrate how an acoustic phonon bath when coupled to a quantum dot with the help of a bichromatic laser field may effectively form a quantum squeezed reservoir. This approach allows one to achieve an arbitrary degree of squeezing of the effective reservoir and it incorporates the properties of the reservoir into two parameters, which can be controlled by varying the ratio of the Rabi frequencies of the bichromatic field. It is found that for unequal Rabi frequencies, the effective reservoir may appear as a quantum squeezed field of ordinary or inverted harmonic oscillators. When the Rabi frequencies are equal the effective reservoir appears as a perfectly squeezed field in which the decay of one of the polarization quadratures of the quantum dot dipole moment is inhibited. The decay of the quantum dot to a stationary state which depends on the initial coherence is predicted. This unusual result is shown to be a consequence of a quantum-nondemolition type coupling of the quantum dot to the engineered squeezed reservoir. The effect of the initial coherence on the steady-state dressed-state population distribution and the fluorescence spectrum is discussed in details. The complete polarization of the dressed state population and asymmetric spectra composed of only a single Rabi sideband peak are obtained under strictly resonant excitation.

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Phonon-assisted incoherent excitation of a quantum dot and its emission properties

Cited by 72 publications

References 32 publications

Spectral asymmetries in the resonance fluorescence of two-level systems under pulsed excitation

Spectral asymmetries in the resonance fluorescence of two-level systems under pulsed excitation

Optical control of nonlinearly dressed states in an individual quantum dot

Engineering a squeezed phonon reservoir with a bichromatic driving of a quantum dot

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