Evaluation of the Hartree‐Fock Theory of the Excitonic Optical Stark Effect

Abstract

In addition, effects due to the time dependence of the fields are studied, taking pump pulse width, polarization relaxation time and the time delay betwetn pump-and probe pulse into account. Deviations from the time independent Hartree-Pock calculations occur both, with respect t o the shift itself and with respect t o the shape of the outcoming signal. The results do not reflect all feetures of earlier experiments, but they are in agreement with recent experimental observations. I m Rahmen der Hartroe-Fock-Theorie werden Absorptionsspektren eines Testpukes berechnet und analysiert, wobei der Halbleiter nichtresonant durch einen Pumppuls angeregt wird. Im Gegensatz zum atomaren optischen Starkeffekt erhLlt man eine Blauverschiebung der Exzitonenenergie verbunden mit einer nahezu konstanten (2d) beziehungsweise leicbt eteigenden (3d) exzitonischen Oszillatorstarke. Dmiiber hinaus werden zeitabhangige Effekte in Abhiingigkeit vcn der 'Pulsdauer, der Phasenrelaxationszeit und der Zeitverzogerung zwischen Pump-und Testpuls untersucht. Sowohl beziiglich der Energieverschiebung selbet als auch der hderung der Linienform des Amgangssignals treten Abweichungen zur zeitunabhangigen Hartree-Fock Rechnung auf. Die Egebnisss beschreiben nicht alle Details friiherer Experimente, werden jedoch dnrch neuere experimentelle Beobachtmgen beetatigt.

Influence of light holes on the heavy-hole excitonic optical Stark effect

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Ultrafast Transient Nonlinear Optical Processes in Semiconductors

“…Numerical calculations based on the theory of Refs. [58,59] predicted that in 2D and for pump detunings of about lORy, low-intensity nonresonant excitation should produce a pure Stark shift of the IS exciton without any loss of oscillator strength, while in 3D the oscillator strength increases slightly with pump intensity [71][72][73][74]. The physical origin of this behavior is that the Stark shift of the band gap is always larger than that of the IS-exciton because of the larger spatial extent of scattering states.…”

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