Influence of a phonon bath on the hierarchy of electronic densities in an optically excited semiconductor

Axt, Vollrath M.; Victor, K.; Stahl, A.

doi:10.1103/physrevb.53.7244

Cited by 81 publications

(140 citation statements)

References 36 publications

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“…In undoped semiconductors, this hierarchy truncates if one adopts an expansion in terms of the optical fields. 4,8,9,10,11,12 This is the case since (a) in the ground state, the conduction band is empty and the valence band is full, and (b) the Coulomb-induced coupling of the conduction and valence bands via, e.g., Auger-like processes is negligible: in the absence of optical fields, the numbers of conduction band electrons and valence band holes are independently conserved. In undoped semiconductors, the lowest electronic excitations of the ground state electrons are the high energy interband e-h pairs, which can adjust almost instantaneously to the dynamics of the photoexcited carriers.…”

Section: 9mentioning

confidence: 99%

“…8,10,11,15 In this theory, the response of the semiconductor is expanded in terms of the number of created e-h pairs. Importantly, the Coulomb interactions that contribute to a specified order in the applied field only occur between such e-h pairs.…”

Section: 9mentioning

confidence: 99%

“…The latter condition is not met however in doped quantum wells, where a correlated 2DEG is present in the ground state, and the DCTS fails there. 11 A new method that extends the DCTS principles to systems with a strongly correlated ground state is required. In a series of works we applied a theory based on a canonical transformation and time-dependent coherent states to study the case where the interactions between the photoexcited e-h pairs and the electron Fermi sea (FS) excitations dominate the coherent nonlinear optical response.…”

Section: 9mentioning

confidence: 99%

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Ultrafast nonlinear optical response of strongly correlated systems: Dynamics in the quantum Hall effect regime

et al. 2003

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We present a theoretical formulation of the coherent ultrafast nonlinear optical response of a strongly correlated system and discuss an example where the Coulomb correlations dominate. We separate out the correlated contributions to the third-order nonlinear polarization, and identify non-Markovian dephasing effects coming from the non-instantaneous interactions and propagation in time of the collective excitations of the many-body system. We discuss the signatures, in the time and frequency dependence of the four-wave-mixing (FWM) spectrum, of the inter-Landau level magnetoplasmon (MP) excitations of the two-dimensional electron gas (2DEG) in a perpendicular magnetic field. We predict a resonant enhancement of the lowest Landau level (LL) FWM signal, a strong non-Markovian dephasing of the next LL magnetoexciton (X), a symmetric FWM temporal profile, and strong oscillations as function of time delay, of quantum kinetic origin. We show that the correlation effects can be controlled experimentally by tuning the central frequency of the optical excitation between the two lowest LLs.

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Section: 9mentioning

confidence: 99%

Section: 9mentioning

confidence: 99%

Section: 9mentioning

confidence: 99%

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Ultrafast nonlinear optical response of strongly correlated systems: Dynamics in the quantum Hall effect regime

et al. 2003

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“…As we have pointed out in the introduction, and as it is known from semiconductor nonlinear optics [9,26], the theory describing the dynamics of the semiconductor electrons interacting with a light field has the structure of an open hierarchy of dynamical variables. Whenever one is dealing with an open hierarchy of dynamical objects, one is facing the problem of finding an appropriate termination procedure.…”

Section: The Exciton-photon Systemmentioning

confidence: 99%

Signatures of the electromagnetic field quantization in the nonlinear optical response of excitons

Savasta¹,

Girlanda²

1999

J. Phys.: Condens. Matter

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Abstract. We present a fully quantum mechanical theory for an interacting system of photons and Coulomb correlated electrons and holes in a semiconductor, using a pertubation series in the exciting laser field. The theory provides microscopic descriptions of nonlinear optical processes in semiconductors related to the electromagnetic field quantization. As an application of the theory we show that it is possible to transfer the exciton-exciton Coulomb correlation to photons, thus producing pairs of near-gap photons with a high degree of quantum entanglement. The photon pairs emerge from the spontaneous optical decay of biexcitons into two polaritons. The pair intensity correlations, calculated in the low density limit for a CuCl slab and for semiconductor microcavities, exhibit quantum features which can be observed by coincidence detection.

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“…9 In the low-excitation regime the relation B ␣ Ӎ͉0͗͘E 1,␣ ͉ can be assumed and it can be shown that the operators B ␣ behave as Boson operators. 17 Within these assumptions, the Hamiltonian determining the dynamics of the semiconductor system is given by the three contributions: the bare excitonic Hamiltonian of the semiconductor system, the interaction Hamiltonian of the semiconductor with the quantum ͑possibly inhomogeneous͒ light field and the interaction Hamiltonian of excitons with the phonon bath determining inelastic scattering and dephasing. 9 The kinetic equation for diagonal terms of the exciton dena͒ Author to whom correspondence should be addressed; electronic mail: pistone@unime.it sity matrix N ␣ ϭ͗B ␣ † B ␣ ͘ can be derived starting from the Heisenberg equation of motion for the exciton operators under the influence of H. The main approximations are the neglect of possible coherent phonon states and of memory effects induced by the photon and phonon fields.…”

Section: ͑1͒mentioning

confidence: 99%

Microscopic quantum theory of spatially resolved photoluminescence in semiconductor quantum structures

Pistone

Savasta

Stefano

et al. 2004

Applied Physics Letters

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We present a microscopic analysis of spatially resolved photoluminescence and photoluminescence excitation spectroscopy in semiconductor quantum structures. Such theoretical and numerical framework provides a general basis for the description of spectroscopic imaging in which the excitation and detection energies and spatial positions can all independently be scanned. The numerical results clarify the impact of the near-field optical setup on the obtained images and resolutions. ͓DOI: 10.1063/1.1711184͔In recent years, measurements based on spatially resolved photoluminescence ͑PL͒ provided direct information on the spatial and energy distribution of light emitting nanometric centers of semiconductor quantum structures, thus opening a rich area of physics involving spatially resolved quantum systems in a complex solid state environment. [1][2][3][4][5][6] In particular, near-field optical microscopy and spectroscopy can detect the optical characteristics of individual quantum dots ͑QDs͒ among, e.g., a high-density ensemble of naturally formed QDs, 7 whereas usual far-field methods provide only ensemble-averaged properties. Detailed simulations of Zimmermann, Runge, and Savona 8,9 have clarified many aspects of the intrigued nonequilibrium dynamics giving rise to photoluminescence spectra in these quantum structures. However, theoretical simulations of near-field imaging spectroscopy of semiconductor quantum structures focus on calculations of local absorption. [10][11][12][13] In contrast, as a matter of fact, almost all experimental images are obtained from PL measurements. Here we present a microscopic theory of spatially resolved photoluminescence in quantum structures that includes both light quantization ͑essential to describe radiative recombination͒ and phonon scattering. The theory also includes the description of spatially confined excitation ͑illumination mode͒ and/or detection ͑collection mode͒. It is worth noting that we are faced with a strictly nonequilibrium problem. Nonequilibrium here arising from both radiative recombination ͑preventing full thermalization͒ and from the local nature of the excitation source ͑in the illuminationmode setup͒. We are also faced with the problem of the differences between illumination (I) and collection (C) scanning near-field optical microscopy ͑SNOM͒ instruments. The equivalence between these two working modes has been established on the basis of the reciprocity theorem for electromagnetic fields. 14 However, this theorem holds for linear and passive media. While semiconductor structures, at low excitation densities, show a linear behavior, phonon scattering and radiative recombination prevent them from being passive.The positive frequency components of the operator describing the signal that can be detected by a general nearfield setup can be expressed as 15 Ŝ t ϩ ϭÂ bg ϩ ϩŜ ϩ , where Â bg ϩ is the elastic background signal ͑largely uniform along the x -y plane͒ proportional to the input electric-field operator, and Ŝ ϩ is related to the sample polarization densi...

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Influence of a phonon bath on the hierarchy of electronic densities in an optically excited semiconductor

Cited by 81 publications

References 36 publications

Ultrafast nonlinear optical response of strongly correlated systems: Dynamics in the quantum Hall effect regime

Ultrafast nonlinear optical response of strongly correlated systems: Dynamics in the quantum Hall effect regime

Signatures of the electromagnetic field quantization in the nonlinear optical response of excitons

Microscopic quantum theory of spatially resolved photoluminescence in semiconductor quantum structures

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