Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Physical review. B, Condensed matter

Dephasing in the quasi-two-dimensional exciton-biexciton system

W. Langbein, J. M. Hvam

Published Jan 15, 2000• 93 citations
Publisher

Abstract

The polarization decay in the exciton-biexciton system of a homogeneously broadened single quantum well is studied by transient four-wave mixing. All three decay rates in the exciton-biexciton three-level system are deduced. The relation between the rates unravels correlations between scattering processes of excitons and biexcitons. Density and temperature dependences show that the involved processes are mainly radiative decay and phonon scattering. The radiative decay rate of the biexcitons is found to be comparable to the one of the excitons, and the involved spontaneous photon emissions from excitons and biexcitons are mutually uncorrelated. In contrast, the biexciton phonon scattering is twice as fast and correlated to exciton-phonon scattering, indicating the interaction with similar phonon modes.

DOI
10.1103/physrevb.61.1692

Related papers

Temperature Dependence of the Dephasing of Excitonic and Biexcitonic Polarization in a ZnSe Single Quantum Well

T. Voss

The polarization decay of the exciton and bound‐biexciton states in a ZnSe single quantum well was studied as a function of the temperature in real‐time‐resolved pulse‐transmission and spectrally resolved four‐wave‐mixing experiments. Optical and acoustic‐phonon scattering coefficients for both resonances were determined and found to be comparable. Additionally, the impact of the dephasing of the coherent excitonic polarization on coherent‐control experiments was analyzed as a function of the sample temperature.

AIP conference proceedings•Jan 1, 2005•0 citations

Ultrafast nonlinear optics in GaAs/AlGaAs quantum wells

J. M. Hvam, D. Birkedal, Vadim G. Lyssenko +2 more

By degenerate four-wave mixing experiments in a two-beam geometry, we have investigated the initial coherence and dephasing of quasi two-dimensional excitions and biexcitons in GaAs multiple quantum wells. The dephasing has contributions from phonon scattering, interface-roughness scattering and exciton-exciton scattering. Inhomogeneous broadening and generation of coherent wavepackets play a significant role in the coherent exciton dynamics. The incoherent exciton dynamics, diffusion and recombination, is studied by three-beam transient grating experiments. A significant difference in the interface roughness scattering of coherent and incoherent (thermalized) excitons is observed.

Physica Scripta•Jan 1, 1994•9 citations

Polarization dependence and selection rules of transient four-wave mixing in GaAs quantum-well excitons

Henry H. Yaffe, James P. Harbison, Leigh T. Florez +1 more

We report the experimental results of two-pulse transient four-wave mixing near the first heavy-hole quantum-well exciton. Input pulses with similar polarizations (circular or linear) measure the exciton dephasing rate; opposite circular polarized pulses produce no four-wave mixing signal, while crossed linear polarized pulses generate a weaker signal with a faster dephasing rate. This signal is attributed to the biexcitonic transition, which was directly observed in a separate nondegenerate four-wave mixing experiment. The selection rules for these transitions are discussed and confirm the treatment of the excitonic transition as a three-level system.

Journal of the Optical Society of America B•Apr 1, 1993•51 citations

Coherent Exciton and Biexciton Nonlinearities in Semiconductor Nanostructures: Effects of Disorder

W. Langbein, Paola Borri, J. M. Hvam

The coherent response of excitons in semiconductor nanostructures measured in four-wave mixing (FWM) depends strongly on the inhomogeneous broadening of the exciton transition. We investigate GaAs/Al0.3Ga0.7As single quantum wells (SQW) and AlxGa1-xAs mixed crystals. Additional to the usual phase-space filling nonlinearity, excitation-induced dephasing (EID) and biexciton formation (BIF) are important. EID leads to a strong dependence of the signal on the angle between the linear input polarizations. We find that EID persists in inhomogeneous systems, showing that the mutual density-dependent dephasing rate difference between two subsystems within the inhomogeneous distribution is strongly dependent on their energy difference. BIF is strongly affecting the cross-linear polarized FWM response. The signal for positive delay is dominated by the transitions from the one-exciton state X to the two-exciton states. Here, the third-order polarization at X-XX is not at the same resonance as the first-order polarization at 0-X. Consequently, the rephasing of the microscopic third-order polarization to the macroscopic FWM photon echo is blurred by the non-perfect correlation of X and XX energies, leading to a fast and non-exponential signal decay in delay time. For inhomogeneous broadenings larger than the biexciton binding energy, we find an enhanced biexciton binding energy, and a quenching of the oscillator strength of the unbound biexciton.

Materials science forum•Dec 1, 1998•5 citations

Pure dephasing induced by exciton-phonon interactions in GaAs quantum dots

Hailin Wang, Xudong Fan, T. Takagahara +1 more

Summary form only given.We report studies of exciton dephasing in quantum dot (QD)-like islands in narrow GaAs quantum wells (QWs). Using three pulse transient four-wave mixing (FWM), we compare dephasing rates directly with population decay rates. This comparison reveals a pure dephasing process that dominates excitonic dephasing at elevated temperatures but does not involve exciton population relaxation.

Conference on Lasers and Electro-Optics•Nov 27, 2002•0 citations

Spectral signatures of χ^(5) processes in four-wave mixing of homogeneously broadened excitons

W. Langbein, T. Meier, S. W. Koch +1 more

The influence of fifth-order coherences on the spectrally resolved four-wave mixing response of predominantly homogeneously broadened quasi-two-dimensional excitons is studied. Fifth-order signatures are discussed as a function of spectral position and excitation polarization. An exciton–biexciton beating for positive delay times is the dominant effect, which is pronounced at the exciton–biexciton transition for collinearly polarized excitation and at the exciton transition for cross-linearly polarized excitation. For negative delay times and collinearly polarized excitation a pronounced exciton–biexciton beating at the exciton resonance is observed that is vanishing for long negative delays owing to the faster dephasing in the two-exciton continuum compared with the bound biexciton state. These results are in qualitative agreement with microscopic model calculations that include the coherent dynamics of one- and two-exciton resonances up to the fifth order in the optical field.

Journal of the Optical Society of America B•Sep 1, 2001•44 citations
The polarization decay in the exciton-biexciton system of a homogeneously broadened single quantum well is studied by transient four-wave mixing. All three decay rates in the exciton-biexciton three-level system are deduced. The relation between the rates unravels correlations between scattering processes of excitons and biexcitons. Density and temperature dependences show that the involved processes are mainly radiative decay and phonon scattering. The radiative decay rate of the biexcitons is found to be comparable to the one of the excitons, and the involved spontaneous photon emissions from excitons and biexcitons are mutually uncorrelated. In contrast, the biexciton phonon scattering is twice as fast and correlated to exciton-phonon scattering, indicating the interaction with similar phonon modes.
The polarization decay of the exciton and bound‐biexciton states in a ZnSe single quantum well was studied as a function of the temperature in real‐time‐resolved pulse‐transmission and spectrally resolved four‐wave‐mixing experiments. Optical and acoustic‐phonon scattering coefficients for both resonances were determined and found to be comparable. Additionally, the impact of the dephasing of the coherent excitonic polarization on coherent‐control experiments was analyzed as a function of the sample temperature.
By degenerate four-wave mixing experiments in a two-beam geometry, we have investigated the initial coherence and dephasing of quasi two-dimensional excitions and biexcitons in GaAs multiple quantum wells. The dephasing has contributions from phonon scattering, interface-roughness scattering and exciton-exciton scattering. Inhomogeneous broadening and generation of coherent wavepackets play a significant role in the coherent exciton dynamics. The incoherent exciton dynamics, diffusion and recombination, is studied by three-beam transient grating experiments. A significant difference in the interface roughness scattering of coherent and incoherent (thermalized) excitons is observed.
We report the experimental results of two-pulse transient four-wave mixing near the first heavy-hole quantum-well exciton. Input pulses with similar polarizations (circular or linear) measure the exciton dephasing rate; opposite circular polarized pulses produce no four-wave mixing signal, while crossed linear polarized pulses generate a weaker signal with a faster dephasing rate. This signal is attributed to the biexcitonic transition, which was directly observed in a separate nondegenerate four-wave mixing experiment. The selection rules for these transitions are discussed and confirm the treatment of the excitonic transition as a three-level system.
The coherent response of excitons in semiconductor nanostructures measured in four-wave mixing (FWM) depends strongly on the inhomogeneous broadening of the exciton transition. We investigate GaAs/Al0.3Ga0.7As single quantum wells (SQW) and AlxGa1-xAs mixed crystals. Additional to the usual phase-space filling nonlinearity, excitation-induced dephasing (EID) and biexciton formation (BIF) are important. EID leads to a strong dependence of the signal on the angle between the linear input polarizations. We find that EID persists in inhomogeneous systems, showing that the mutual density-dependent dephasing rate difference between two subsystems within the inhomogeneous distribution is strongly dependent on their energy difference. BIF is strongly affecting the cross-linear polarized FWM response. The signal for positive delay is dominated by the transitions from the one-exciton state X to the two-exciton states. Here, the third-order polarization at X-XX is not at the same resonance as the first-order polarization at 0-X. Consequently, the rephasing of the microscopic third-order polarization to the macroscopic FWM photon echo is blurred by the non-perfect correlation of X and XX energies, leading to a fast and non-exponential signal decay in delay time. For inhomogeneous broadenings larger than the biexciton binding energy, we find an enhanced biexciton binding energy, and a quenching of the oscillator strength of the unbound biexciton.
The influence of fifth-order coherences on the spectrally resolved four-wave mixing response of predominantly homogeneously broadened quasi-two-dimensional excitons is studied. Fifth-order signatures are discussed as a function of spectral position and excitation polarization. An exciton–biexciton beating for positive delay times is the dominant effect, which is pronounced at the exciton–biexciton transition for collinearly polarized excitation and at the exciton transition for cross-linearly polarized excitation. For negative delay times and collinearly polarized excitation a pronounced exciton–biexciton beating at the exciton resonance is observed that is vanishing for long negative delays owing to the faster dephasing in the two-exciton continuum compared with the bound biexciton state. These results are in qualitative agreement with microscopic model calculations that include the coherent dynamics of one- and two-exciton resonances up to the fifth order in the optical field.