Interwell excitons in GaAs superlattices

Birkedal, D.; Sayed, K. El; Sanders, G. D.; Spiegelberg, Christine; Lyssenko, V. G.; Stanton, C. J.; Hvam, Jørn Märcher; Timofeev, V. B.; Bayer, М.

doi:10.1103/physrevb.54.10316

Cited by 32 publications

(23 citation statements)

References 17 publications

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“…The decay does not depend on the details of the coupling between the continuum states and exciton, but it is important to know how it arises. Earlier work 24,25 only included EID, however, we observe that similar shifts of the exciton are observed in SR-DT for excitation in the continuum. This indicates that EIS also contributes strongly to the coupling.…”

supporting

confidence: 78%

“…As noted previously, quantum interference due to exciting continuum states causes a rapid decay of the experimental data. [23][24][25] This is not included in our simple theory; this theory shows a slight rise for increasing delay, while the experiment de- cays immediately. For negative delay, the agreement is very good, including the faster decrease of the high-energy peak in the spectrum for both theory and experiment.…”

mentioning

confidence: 91%

“…In addition, quantum interference due to excitation of continuum states causes the time integrated signal to decay rapidly as a function of delay. [23][24][25] To overcome this, we spectrally resolve the signal and observe a splitting in the peak, although the absorption spectrum shows only a single peak. Numerical calculations using modified optical Bloch equations show that only EIS can result in such a split peak.…”

mentioning

confidence: 97%

“…This has been explained in terms of quantum interference arising from coupling between the exciton and continuum states. [23][24][25] Any coupling between the exciton and continuum causes rapid decay of the TFWM signal due to destructive interference. The decay does not depend on the details of the coupling between the continuum states and exciton, but it is important to know how it arises.…”

mentioning

confidence: 99%

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Role of excitation-induced shift in the coherent optical response of semiconductors

Shacklette

Cundiff

2002

Phys. Rev. B

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A transient four-wave-mixing signal is shown to arise from an excitation induced shift. In semiconductors, this signal can be comparable to or stronger than signals arising from saturation, local fields, or excitation induced dephasing. Calculations using modified optical Bloch equations show that multiple peaks in the transient four-wave-mixing spectrum are a signature of an excitation induced shift contributing to the signal. We observe this experimentally from a semiconductor multiple quantum well and confirm the presence of a shift directly using spectrally resolved differential transmission.The interaction between light and semiconductors provides fundamental insight into the dynamics of the optically created excitations. This is particularly true when techniques that are sensitive to coherence are employed. Coherent spectroscopy is well understood for a dilute vapor, where only isolated atoms or molecules need to be considered. 1 In dense materials, such as semiconductors or a dense atomic vapor, many-body interactions lead to dramatic differences from the dilute limit. 2 These effects can completely alter the interpretation of spectroscopic measurements and the performance of optoelectronic devices.Substantial progress has been made in understanding how interactions among elementary optical excitations ͑excitons or unbound electron-hole pairs͒ influence the coherent optical response of semiconductors, which is typically observed using transient four-wave mixing ͑TFWM͒. Early work 3-5 was interpreted based on the optical Bloch equations ͑OBE's͒, 6 which are appropriate in the dilute limit. Subsequently, it was realized that in addition to the signals arising from saturation, which are described by the OBE's, there were additional signals due to the interactions. The appearance of a signal for ''negative'' delay in a two-pulse TFWM experiment and a delay in the emission as a function of real time 7,8 are the most dramatic signatures. These effects can be calculated using a full many-body treatment. 9,10 In addition, they can be described phenomenologically in a few-level approach as arising from local fields, 11,12 excitation induced dephasing ͑EID͒, 13-15 and biexcitonic effects. 16,17 The phenomenological approach yields corrections to the OBE's, which can produce very good agreement with experiment 18 including complex polarization selection rules. 19 While the full many-body treatment is clearly based on a stronger theoretical foundation, the phenomenological description is usually easier to understand in terms of the underlying physics. The foundation provided by the full many-body treatment has been used to develop a microscopic basis for the phenomenological few level approach. 20 We show that an excitation induced shift ͑EIS͒ can result in a TFWM signal similar to that produced by the other mechanisms listed above. EIS is a manifestation of fundamental many-body interactions that result in a modification of the excitonic frequency in the presence of an excited carrier population. While the presence o...

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supporting

confidence: 78%

mentioning

confidence: 91%

mentioning

confidence: 97%

mentioning

confidence: 99%

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Role of excitation-induced shift in the coherent optical response of semiconductors

Shacklette

Cundiff

2002

Phys. Rev. B

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“…Without going into details, we note that they lead either to faster dephasing and resonance broadening due to the exciton-free carrier collisions, 20 or to quenching of the TFWM signal for delays, exceeding the temporal width of the laser pulse. 21,22 Both effects will impede the experimental observation of the quantum beats.…”

Section: B Biexciton Bindingmentioning

confidence: 99%

Binding of biexcitons in GaAs/AlxGa1−
Mizeikis
¹
,
Birkedal
²
,
Langbein
³

et al. 1997
Phys. Rev. B
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Properties of the heavy-hole excitons and biexcitons in GaAs/Al 0.3 Ga 0.7 As superlattices are studied using linear and nonlinear optical techniques. In superlattices with miniband halfwidths less than the exciton binding energy, the biexciton binding energy is found to be the same as in the noninteracting multiple quantum wells of the same width. When the miniband halfwidth exceeds the exciton binding energy, the biexciton binding energy decreases abruptly to the bulk value. ͓S0163-1829͑97͒02008-0͔

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Coulomb Correlations and Biexciton Signatures in Coherent Excitation Spectroscopy of Semiconductor Quantum Wells

Finger

Kraft

Hofmann

et al. 2002

phys. stat. sol. (b)

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The influence of coupling, correlation, and disorder on exciton and biexciton signatures is investigated using coherent excitation spectroscopy. Different biexciton-induced transitions of a single biexciton state are spectrally resolved. One of the transitions is found to be particularly sensitive to disorder. Mixed biexciton resonances, resulting from attractively interacting heavy and light hole exciton states, are identified. The observations are analyzed on the basis of microscopic model calculations.

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Interwell excitons in GaAs superlattices

Cited by 32 publications

References 17 publications

Role of excitation-induced shift in the coherent optical response of semiconductors

Role of excitation-induced shift in the coherent optical response of semiconductors

Binding of biexcitons in GaAs/AlxGa1−
Mizeikis
¹
,
Birkedal
²
,
Langbein
³

et al. 1997
Phys. Rev. B
Self Cite
18
1
8
0
View full text Add to dashboard Cite

Coulomb Correlations and Biexciton Signatures in Coherent Excitation Spectroscopy of Semiconductor Quantum Wells

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Interwell excitons in GaAs superlattices

Cited by 32 publications

References 17 publications

Role of excitation-induced shift in the coherent optical response of semiconductors

Role of excitation-induced shift in the coherent optical response of semiconductors

Binding of biexcitons in GaAs/AlxGa1−Mizeikis1, Birkedal2, Langbein3 et al. 1997Phys. Rev. BSelf Cite18180View full textAdd to dashboardCite

Coulomb Correlations and Biexciton Signatures in Coherent Excitation Spectroscopy of Semiconductor Quantum Wells

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Resources

About

Binding of biexcitons in GaAs/AlxGa1−
Mizeikis
¹
,
Birkedal
²
,
Langbein
³

et al. 1997
Phys. Rev. B
Self Cite
18
1
8
0
View full text Add to dashboard Cite