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Identifier	000424541
Title	Electron quantum path interferences in strongly laser driven aligned molecules and generation of circularly polarized XUVpulses
Alternative Title	Φαινόμενα συμβολής κβαντικών διαδρομών ηλεκτρονίων από ευθυγραμμισμένα μόρια σε ισχυρά πεδία λέιζερ και παραγωγή κυκλικά πολωμένης XUV ακτινοβολίας.
Author	Χατζηαθανασίου, Στέφανος
Thesis advisor	Χαραλαμπίδης, Δημήτριος Τζάλλας, Παρασκευάς
Reviewer	Κομίνης, Ιωάννης Ρακιτζής, Θεόδωρος Ηλιόπουλος, Ελευθέριος Πισσαδάκης Σταύρος Petrosyan, David
Abstract	The aim of the thesis is to unravel the dynamics of the High Harmonic Generation (HHG) process induced in strongly laser driven aligned molecules and develop a method for the production of circularly polarized ultrashort pulses in the extreme-ultraviolet (XUV) spectral range. Towards these goals we have used the Time Gated Ion Microscopy (IM) technique and a pump-probe arrangement. The former maps the spatial XUV intensity distribution onto a spatial ion distribution (produced in the XUV focal area through a single–XUV– photon ionization process of an atomic gas). The pump–probe arrangement was used to trigger the molecular alignment process and generate the high–harmonics. Initially, in order to calibrate the harmonic generation/detection scheme, we have used only the IM and Argon (Ar) atoms for the generation of high-harmonics. In this experiment we have measured and quantified the influence of spatiotemporal coupling effects in HHG region. After, using N2 molecules and the IM approach in combination with the pump-probe arrangement, we have spatially resolved the interference pattern produced by the spatiotemporal overlap of the harmonics emitted by the short– and long–electron quantum paths, and we have succeeded in measuring in-situ their phase difference and disclose their dependence on molecular alignment. The findings constitute a vital step towards understanding of strong-field molecular physics and the development of a self-referenced attosecond spectroscopy approach. Additionally using the same pump-probe arrangement we demonstrate a method for the generation of circularly polarized XUV radiation using CO2 molecules, a matter which is important for investigating phenomena such as circular dichroism, ultrafast spin dynamics, magnetic microscopy, chirality assignment e.t.c.
Language	English
Subject	High harmonic generation
	Molecular alignment
	Μοριακή ευθυγράμμιση
	Παραγωγή αρμονικών υψηλής τάξης
Issue date	2019-09-09
Collection	School/Department--School of Sciences and Engineering--Department of Physics--Doctoral theses
	Type of Work--Doctoral theses
Permanent Link	https://elocus.lib.uoc.gr//dlib/6/a/1/metadata-dlib-1567770585-884416-2542.tkl
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