SKM 2023 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 35: Focus Session: Transient multi-wave mixing on excitonic resonances

HL 35.2: Hauptvortrag

Donnerstag, 30. März 2023, 10:00–10:30, POT 251

Impact of phonons on time-resolved optical signals from excitons — •Doris E. Reiter — Condensed Matter Theory, TU Dortmund, 44221 Dortmund

A major difference between optical manipulation of atoms and excitons in semiconductors is the interaction of the latter with the vibrational modes of the solid, i.e., the phonons. In particular in nanostructures like quantum dots, the interaction with acoustic phonons is non-monotonous as function of energy, yielding interesting phenomena like phonon sidebands, reappearance of Rabi rotations or phonon-assisted state preparation. When a quantum dot is optically driven exhibiting Rabi oscillations of the exciton, the pure dephasing-type electron-phonon interaction results in polaron formation accompanied by the emission of phonon wave packets. While for the occupation, the phonon influence leads to an exponential damping, optical multi-wave mixing experiments are more sensitive to the quantum dot polarization. Here, the phonons cannot be described by a simple damping, but their interaction can be understood as a relaxation into the lower dressed state. In this talk, we use a simple model of phonons [1] to discuss their impact on time-resolved optical signals in semiconductor quantum dots. We consider the impact of phonon on continuous wave excitation in a pump-probe configuration [1] and on optical photon echo signals, where the model is in excellent agreement with experiments [2]. Ref: [1] Ann. Phys. 533, 2100086 (2021) [2] PRB 106, 205408 (2022).