Ultrafast Transient Nonlinear Optical Processes in Semiconductors

Chemla, D. S.

doi:10.1016/s0080-8784(08)62722-2

Cited by 45 publications

(52 citation statements)

References 175 publications

(224 reference statements)

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“…Figure 2 shows the differential absorption (∆A) spectra of the CdSe NCs in PBMA. The negative signal corresponds to ground state bleaching, and the positive-signed signal corresponds to increased absorption, indicative of transient absorption or associated with many-body effects related to the optical Stark effect [14]. The ∆A spectra are dominated by the strong negative band around 574 nm (2.16 eV), which is related to saturation of the lowest energy transition [1S(e)-1S 3/2 (h)].…”

Section: Resultsmentioning

confidence: 99%

Surface passivation in CdSe nanocrystal–polymer films revealed by ultrafast excitation relaxation dynamics

Kovalevskij¹,

Gulbinas

Piskarskas

et al. 2004

Physica Status Solidi (b)

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PACS 78.40.+y, 78.47.+p, 78.55.Et, 78.67.Bf The photoluminescence efficiencies and excitation relaxation dynamics in CdSe nanocrystals (NC) passivated with tri-n-octylphosphine oxide and embedded in two different polymer matrixes, poly(styrene) (PS) and poly(butylmethacrylate) (PBMA), are compared. Femtosecond pump-probe absorption spectroscopy is used to clarify the influence of various transparent polymer matrixes on the electronic properties and excitation relaxation dynamics of quantum confined CdSe semiconductor nanocrystals of 5.0 nm diameter. The fluorescence intensity is reported to be ~10 times higher for the NC-PS sample compared to the NC-PBMA film. This striking difference in fluorescence yield is shown to be related to markedly different rates of nonradiative excitation relaxation in the two samples, and is attributed directly to a role played by the polymer host.

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Section: Resultsmentioning

confidence: 99%

Surface passivation in CdSe nanocrystal–polymer films revealed by ultrafast excitation relaxation dynamics

Kovalevskij¹,

Gulbinas

Piskarskas

et al. 2004

Physica Status Solidi (b)

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“…Such work has reinforced the notion that nonlinear optical experiments are well-suited for the elucidation of many-body correlations because the infinite many-body problem is factorized according to the order of the nonlinear spectroscopy [40,43]. It has been found that the key contributions to the third-order nonlinear optical response include two-particle correlations, Pauli blocking (also known as phase space filling) and the bare Coulomb interaction [9,12,41]. These effects are described at the Hartree-Fock/Random Phase Approximation (HF/RPA) level.…”

Section: Simulationsmentioning

confidence: 95%

“…However, semiconductors interact with light in fundamentally different ways than 'two-level' systems such as atoms or molecules. It turns out that higher-order correlations also make important contributions at the (3) c level [9,12,42]. Coulomb correlations beyond HF/RPA as well as biexciton-exciton interactions must be considered.…”

Section: Simulationsmentioning

confidence: 99%

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Photon echo studies of biexcitons and coherences in colloidal CdSe quantum dots

Colonna¹,

Yang²,

Scholes³

2005

Physica Status Solidi (b)

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PACS 71.35.Cc, 78.47.+p, 78.67.Hc Nonlinear optical properties of colloidal quantum dots are studied to elucidate the significance and nature of many-body effects. Two-pulse photon echo studies of nanocrystalline CdSe quantum dots are reported for samples dispersed in a poly(butylmethacrylate) film (4.4 K). Oscillations are observed in the experimental data that are attributed to 3/2 1 1 e S S -3/2 2 1 e S S biexciton cohererences. Signals are simulated using a phenomenological model based on the many-body description of the dynamics (the average polarization model). It is found that the electronic coherences and the nonlinear response originating from biexciton source terms are important, but their manifestation in the photon echo signals is strongly influenced by the interplay between homogeneous and inhomogeneous line broadening.

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“…Indeed it is now possible to perform experiments with time resolution shorter than the scattering time scales of the fundamental elementary excitations and with interferometric control of the excitation density and energy. 1,2 However, most of the work, experimental or theoretical, concentrates on either one of two completely different experimental situations, involving, respectively, coherently driven states [3][4][5][6][7] or incoherently relaxing distributions. [8][9][10][11][12][13][14] In real life this distinction is artificial since an initially coherently driven system naturally relaxes and eventually reaches thermodynamic equilibrium.…”

Section: Introductionmentioning

confidence: 99%

Semiconductor polarization dynamics from the coherent to the incoherent regime: Theory and experiment

et al. 2002

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We explore the capability of a many-particle approach to the polarization dynamics of optically excited semiconductors. The theory contains the well-established theories for the coherent low excitation and incoherent high excitation regimes as limiting cases. The approach shows excellent agreement with four-wave mixing experiments where an incoherent background of carriers is created by a cw beam allowing to investigate the full range between the limiting cases.

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Ultrafast Transient Nonlinear Optical Processes in Semiconductors

Cited by 45 publications

References 175 publications

Surface passivation in CdSe nanocrystal–polymer films revealed by ultrafast excitation relaxation dynamics

Surface passivation in CdSe nanocrystal–polymer films revealed by ultrafast excitation relaxation dynamics

Photon echo studies of biexcitons and coherences in colloidal CdSe quantum dots

Semiconductor polarization dynamics from the coherent to the incoherent regime: Theory and experiment

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