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Identifier

000396923

Title

Ultrafast Dynamical properties of strongly interacting systems under nonlinear coherent photoexcitation by multiple ultrashort laser pulses

Alternative Title

Υπερταχείς δυναμικές ιδιότητες με ισχυρές αλληλεπιδράσεις κάτω από μη γραμμική διέγερση από πολλαπλούς παλμούς laser

Author

Καραδημητρίου, Μιχάλης Ε.

Thesis advisor

Περάκης, Ηλίας

Reviewer

Τσιρώνης, Γιώργος
Ζώτος, Ξενοφών
Τζανετάκης, Παναγιώτης
Ρακιτζής, Πέτρος
Ηλιόπουλος, Ελευθέριος
Φρουδάκης, Γεώργιος

Abstract

In this thesis we present a non-equilibrium many{body formulation of the coherent ultrafast nonlinear optical response of doped semiconductors and systems with a strongly correlated ground state, such as the quantum Hall system (QHS). Our theory is based on a truncation of the density matrix equations of motion in the absence of a small interaction parameter, obtained by expanding in terms of the optical field and by using Hubbard operator density matrices to describe the exact dynamics within a subspace of many{body states. We identify signatures of non{instantaneous interactions between magnetoexcitons (X) and the incompressible two{dimensional electron gas (2DEG) during femto- and pico-second timescales by describing X coupling to inter-Landau level magnetoroton (MR) and magnetoplasmon (MP) excitations. We show that strong X coupling to X+MR configurations changes the temporal evolution of the nonlinear optical spectra as compared to the Random Phase Approximation (RPA). and leads to an absorption resonance. We calculate the three-pulse four-wave mixing signal, whose dependence on frequency and two time delays reflects the dephasing and relaxation of the strongly coupled X-2DEG system, and demonstrate that the dynamics of the X-2DEG interaction process can be resolved with femtosecond optical pulses. Our results shed light into unexplored sub-picosecond and coherent dynamics of the QHS and may be used to interpret and guide two-dimensional correlation spectroscopy experiments.

Language

English

Subject

Quantum Hall

Κβαντικό φαινόμενο Hall

Issue date

2015-09-14

Collection

School/Department--School of Sciences and Engineering--Department of Physics--Doctoral theses

Type of Work--Doctoral theses

Views

734

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