Correlation coefficient for dephasing of light-hole excitons and heavy-hole excitons in GaAs quantum wells

Optical two-dimensional Fourier-transform (2DFT) spectroscopy is used to study the coherent optical response of potassium vapor in a thin transmission cell. Rephasing and nonrephasing spectra of the D 1 and D 2 transitions are obtained and compared to numerical simulations. Non-perturbative calculations using the optical Bloch equations give very good agreement with the experimental peak strengths and line shapes. Nonradiative Raman-like coherences are isolated using a different 2DFT projection. Comparison between the optical and Raman linewidths shows that dephasing is due to partially correlated energy fluctuations. Density-dependent measurements show distortion of 2DFT spectra due to pulse propagation effects.

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“…The dephasing rate of the Raman coherence is related to the dephasing rates of the optical transitions by [40] …”

Section: Resultsmentioning

confidence: 99%

Two-dimensional Fourier-transform spectroscopy of potassium vapor

et al. 2010

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“…[34][35][36] The correlation of the inhomogeneity may also affect the investigation of Raman coherence. 39 The 2D correlation spectra that employ S I ͑photon echo͒ show photon-echo signals when displayed as 2D ͑⍀ 3 , ⍀ 1 ͒ spectra for various values of t 2 . Early measurement of Raman coherence between HH and LH excitons in semiconductors was measured by observing oscillations in a transient absorption experiment.…”

Section: Isolating Excitonic Raman Coherence In Semiconductors Using mentioning

confidence: 99%

Isolating excitonic Raman coherence in semiconductors using two-dimensional correlation spectroscopy

Yang

Zhang

Bristow³

et al. 2008

The Journal of Chemical Physics

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We present the experimental and simulation results of two-dimensional optical coherent correlation spectroscopy signals along the phase-matching direction k(I) = -k(1) + k(2) + k(3) projected on the two-dimensional (2D) (Omega(3),Omega(2)) plane corresponding to the second and third delay periods. Overlapping Raman coherences in the conventional (Omega(3),Omega(1)) 2D projection may now be clearly resolved. The linewidths of the heavy-hole (HH) and light-hole (LH) excitonic Raman coherence peaks are obtained. Further insights on the higher-order (beyond time-dependent Hartree-Fock) correlation effects among mixed (HH and LH) two excitons can be gained by using a cocircular pulse polarization configuration.

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“…We find that the quantum beat dephasing time is τ c = 250 ± 30 fs (γ XT = ℏ/τ c 2.6 ± 0.2 meV). The fact that γ XT is equivalent to the sum of the exciton (γ X = 1.4 meV) and trion (γ T = 1.3 meV) dephasing rates implies that dissipative fluctuations that broaden the exciton and trion transition line widths are uncorrelated, which is in contrast to anticorrelated heavy-holelight-hole exciton dephasing in GaAs quantum wells and correlated dephasing of fine-structure exciton states in InAs quantum dots . For the LCP , the nonoscillating component arises from ground-state bleaching and excited state absorption of the exciton transition, which exhibits a faster recombination lifetime compared to the trion (see Figure and Supporting Information).…”

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Coherent and Incoherent Coupling Dynamics between Neutral and Charged Excitons in Monolayer MoSe₂

et al. 2016

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The optical properties of semiconducting transition metal dichalcogenides are dominated by both neutral excitons (electron-hole pairs) and charged excitons (trions) that are stable even at room temperature. While trions directly influence charge transport properties in optoelectronic devices, excitons may be relevant through exciton-trion coupling and conversion phenomena. In this work, we reveal the coherent and incoherent nature of exciton-trion coupling and the relevant timescales in monolayer MoSe2 using optical two-dimensional coherent spectroscopy. Coherent interaction between excitons and trions is definitively identified as quantum beating of cross peaks in the spectra that persists for a few hundred femtoseconds. For longer times up to 10 ps, surprisingly, the relative intensity of the cross peaks increases, which is attributed to incoherent energy transfer likely due to phonon-assisted up-conversion and down-conversion processes that are efficient even at cryogenic temperature.

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Correlation coefficient for dephasing of light-hole excitons and heavy-hole excitons in GaAs quantum wells

Cited by 11 publications

References 31 publications

Two-dimensional Fourier-transform spectroscopy of potassium vapor

Two-dimensional Fourier-transform spectroscopy of potassium vapor

Isolating excitonic Raman coherence in semiconductors using two-dimensional correlation spectroscopy

Coherent and Incoherent Coupling Dynamics between Neutral and Charged Excitons in Monolayer MoSe₂

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Correlation coefficient for dephasing of light-hole excitons and heavy-hole excitons in GaAs quantum wells

Cited by 11 publications

References 31 publications

Two-dimensional Fourier-transform spectroscopy of potassium vapor

Two-dimensional Fourier-transform spectroscopy of potassium vapor

Isolating excitonic Raman coherence in semiconductors using two-dimensional correlation spectroscopy

Coherent and Incoherent Coupling Dynamics between Neutral and Charged Excitons in Monolayer MoSe2

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Coherent and Incoherent Coupling Dynamics between Neutral and Charged Excitons in Monolayer MoSe₂