Coulomb Memory Signatures in the Excitonic Optical Stark Effect

Sieh, C.; Meier, Torsten; Jahnke, F.; Knorr, Andreas; Koch, S. W.; Brick, P.; Hübner, Matthias; Ell, C.; Prineas, J. P.; Khitrova, G.; Gibbs, H. M.

doi:10.1103/physrevlett.82.3112

Cited by 186 publications

(161 citation statements)

References 31 publications

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“…(1) [30]] via the time-dependent amplitudes b s,f (t) is crucial to include the related quantum memory effects (e.g., refs. [34][35][36]) which -as our analysis reveals -give rise to additional unstable modes. According to eq.…”

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confidence: 96%

Large optical gain from four-wave mixing instabilities in semiconductor quantum wells

Schumacher¹,

Kwong²,

Binder³

2007

Europhys. Lett.

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PACS 71.35.-y -Excitons and related phenomena PACS 78.47.+p -Time-resolved optical spectroscopies and other ultrafast optical measurements in condensed matter PACS 42.65.Sf -Dynamics of nonlinear optical systems; optical instabilities, optical chaos and complexity, and optical spatio-temporal dynamicsAbstract.-Based on a microscopic many-particle theory, we predict large optical gain in the probe and background-free four-wave mixing directions caused by excitonic instabilities in semiconductor quantum wells. For a single quantum well with radiative-decay limited dephasing in a typical pump-probe setup we discuss the microscopic driving mechanisms and polarization and frequency dependence of these instabilities.In gaseous atomic or molecular systems and simple Kerr media, four-wave mixing (FWM) processes lead, among other things, to transverse optical instabilities (e.g., refs. [1][2][3][4][5]). The interest in these FWM instabilities has recently been renewed by the demonstration of their effectiveness for all-optical switching at very low light intensities [6,7]. In this Letter we argue on the basis of a microscopic many-particle analysis that FWM instabilities can occur via nonlinear excitonic processes in a single semiconductor quantum well (QW). Instead of studying spontaneous off-axis pattern formation induced by these instabilities, we investigate their role in a pumpprobe setup as illustrated in fig. 1. We find that the FWM instabilities can lead to large gain in the probe and (background-free) FWM directions that grows exponentially with the pump pulse duration, limited by the eventual buildup of incoherent exciton/biexciton densities. Our analysis shows that the materials conditions for observing these instability-induced gains, though quite stringent, appear to be obtainable in currently available highquality QW samples.FWM has been widely used in studies of microscopic processes in QWs (e.g.,). An example of FWM driven instabilities in semiconductors is the parametric amplification of exciton polaritons in planar QW microcavities [16][17][18][19][20][21][22][23]. In contrast to the microcavity, we focus on the "simple" system of a single QW. Using a microscopic many-particle theory we give a comprehensive stability analysis of the optical polarization field in- duced by a normally incident pump beam, treating all vectorial polarization state channels. In atomic systems, phase-space filling (PSF) nonlinearities drive the instabilities, and in microcavities it is the interaction between cocircularly (say, ++) polarized polaritons, related to the Hartree-Fock (HF) interaction and two-exciton (++) correlations [21][22][23]. We find that neither PSF nor excitonic interactions in the ++ channel are promising for instabilities in single QWs, mainly because of excessive excitationinduced dephasing (EID). Instead we show that instabilities and large probe gains can be produced in single QWs by virtual biexciton formation, which requires the pump to

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confidence: 96%

Large optical gain from four-wave mixing instabilities in semiconductor quantum wells

Schumacher¹,

Kwong²,

Binder³

2007

Europhys. Lett.

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“…Although the usefulness of adding a second dimension was recognized in TWFM studies of semiconductors (17)(18)(19)(20), only the intensity of the emitted signal, not the phase-resolved electric field, was measured. The transient absorption experiments clearly show that detecting only the real part of the emitted field is advantageous (21,22), but the effects of inhomogeneous broadening cannot be removed. 2DFTS combines the best features of both, resolving the signal into real and imaginary parts while simultaneously being able to extract the underlying physics despite the presence of inhomogeneity caused by structural disorder.…”

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confidence: 99%

Polarization-dependent optical 2D Fourier transform spectroscopy of semiconductors

Zhang

Кузнецова

Meier

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

116

113

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Optical 2D Fourier transform spectroscopy (2DFTS) provides insight into the many-body interactions in direct gap semiconductors by separating the contributions to the coherent nonlinear optical response. We demonstrate these features of optical 2DFTS by studying the heavy-hole and light-hole excitonic resonances in a gallium arsenide quantum well at low temperature. Varying the polarization of the incident beams exploits selection rules to achieve further separation. Calculations using a full many-body theory agree well with experimental results and unambiguously demonstrate the dominance of many-body physics.excitons ͉ many-body effects ͉ ultrafast O ptical excitation of a direct gap semiconductor, such as gallium arsenide (GaAs), produces electron-hole pairs. The Coulomb attraction between the electron and hole can result in a bound state, known as an exciton, with a hydrogenic wavefunction for the relative coordinate. Excitons have a large oscillator strength because of the proximity of the electron and hole and thus can dominate the absorption spectrum close to the fundamental band gap. In GaAs heterostructures, the exciton binding energy is of order 10 meV; thus, excitonic resonances appear only at low temperatures. Excitons and unbound electron-hole pairs exhibit dynamics on a femtosecond-to-picosecond time scale. These timescales, combined with the strong interaction with light, make ultrafast spectroscopy an ideal tool for studying carrier dynamics in semiconductors.Over the last two decades, excitonic resonances in semiconductors have been studied extensively by using ultrafast spectroscopy, primarily transient four-wave-mixing (TFWM) (1, 2). The measurements clearly showed signatures of many-body effects. The first and most prominent was a signal for the ''wrong'' time delay in a two-pulse TFWM experiment. Theoretically, such signals could arise from several effects including local fields (3, 4), biexcitons (5), excitation-induced dephasing (6, 7), or excitation-induced shift (8). Time resolving the signal also provided evidence for many-body contributions (9, 10), although it did not resolve the ambiguity regarding the underlying phenomena.Recent results using optical 2D Fourier transform spectroscopy (2DFTS) to study the exciton resonances have shown that much more information is obtained, promising a more stringent test of the theory (11). 2DFTS traces its roots to NMR (12). Recently, there has been significant progress in translating multidimensional NMR techniques into the infrared and optical domains for the study of vibrations (13) and electronic excitations (14-16) in molecules. Although the usefulness of adding a second dimension was recognized in TWFM studies of semiconductors (17-20), only the intensity of the emitted signal, not the phase-resolved electric field, was measured. The transient absorption experiments clearly show that detecting only the real part of the emitted field is advantageous (21, 22), but the effects of inhomogeneous broadening cannot be removed. 2DFTS combines the best...

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“…Early numerical solutions have concentrated on effects such as dynamical screening within the screened Hartree-Fock approximation [69,70], whereas the strong excitation and ultrafast regime (in which excitonic phase space filling is the leading nonlinearity) have been investigated extensively in the unscreened Hartree-Fock approximation. More recently, the influence of dynamical correlations in the screened Hartree-Fock approximation (and modifications thereof) on the ultrafast nonlinearities has been investigated [71]. On the other hand, correlations within the x (3) regime, such as biexcitonic effects, have been found to be described within the dynamics-controlled truncation scheme [72][73][74].…”

Section: Phenomenological Inclusion Of Many-body Contributionsmentioning

confidence: 99%

(11 IOTA)-Oriented Heterostructures and Devices: The Effects of Strain and Orientation

Smirl¹

2001

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Coulomb Memory Signatures in the Excitonic Optical Stark Effect

Cited by 186 publications

References 31 publications

Large optical gain from four-wave mixing instabilities in semiconductor quantum wells

Large optical gain from four-wave mixing instabilities in semiconductor quantum wells

Polarization-dependent optical 2D Fourier transform spectroscopy of semiconductors

(11 IOTA)-Oriented Heterostructures and Devices: The Effects of Strain and Orientation

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