dc.contributor.author
Jürgens, Peter
dc.date.accessioned
2021-03-26T10:33:02Z
dc.date.available
2021-03-26T10:33:02Z
dc.identifier.uri
https://refubium.fu-berlin.de/handle/fub188/29788
dc.identifier.uri
http://dx.doi.org/10.17169/refubium-29530
dc.description.abstract
The buildup of an electron-hole plasma during the interaction of a solid dielectric with
intense, ultrashort laser pulses entails a wealth of successive processes. The dynamics
of the strong-field induced plasma are thereby of utmost interest for both fundamental
research as well as for optimizing industrial applications. In particular, the relative
importance of the various excitation mechanisms participating in the production of
the electron-hole plasma is of substantial relevance. This thesis aims at elucidating
the relative contribution of the two major excitation mechanisms - strong-field and
electron-impact ionization - to the generation of an electron-hole plasma in strong-field
driven solid dielectrics.
The first two chapters of this thesis are dedicated to a theoretical description of the
fundamental, ultrafast, light-matter interaction and resulting phenomena. Afterwards,
the experimental apparatus, designed and implemented to enable two-color pump-probe
experiments in transparent solids, is described. Results obtained by characterizing the
absorption of a weak probe laser pulse during propagation through an excited region
of a bulk a-SiO2 sample shed light on the ultrafast excitation and relaxation dynamics
in fused silica. In contrast to previously reported findings, the results show a strong
dependence of the relaxation time on the intensity of the mid-infrared pump laser pulse.
An explanation based on the detrapping of self-trapped carriers due to vibrations of the
crystal lattice is proposed.
In a second set of time-resolved experiments low-order harmonics generated by a two-color
field in fused silica are analyzed regarding their underlying nonlinear generation process.
By linking the experimental results to numerical simulations, a previously unreported
ionization current is identified as the main source of low-order harmonic generation in
strongly excited SiO2. A further analysis of the corresponding phase matching condition indicates that a novel self-quasi-phase matching mechanism, associated with the
formation of a quasi-stationary wave close to the rear surface of the target significantly
enhances the conversion efficiency of the wave mixing process.
Finally, the results are linked and interpreted enabling the reconstruction of the strongfield induced plasma formation and the identification of the relative role of strong-field
and electron-impact ionization. Based on the discussed findings it is demonstrated that
electron-impact ionization is the prevailing excitation mechanism in laser-excited SiO2
at intensities close to the damage threshold.
The presented results offer tremendous potential for future advanced plasma diagnostics and provide an original approach for the optimization of laser-micromachining
applications in dielectric materials
en
dc.format.extent
v, 143 Seiten
dc.rights.uri
http://www.fu-berlin.de/sites/refubium/rechtliches/Nutzungsbedingungen
dc.subject
strong-field ionization
en
dc.subject
plasma formation
en
dc.subject
high harmonic generation
en
dc.subject.ddc
500 Naturwissenschaften und Mathematik::530 Physik::530 Physik
dc.title
Strong-field induced plasma formation in solid dielectrics
dc.contributor.gender
male
dc.contributor.firstReferee
Vrakking, Marc J. J.
dc.contributor.furtherReferee
Baumert, Thomas
dc.date.accepted
2020-12-10
dc.identifier.urn
urn:nbn:de:kobv:188-refubium-29788-7
dc.title.translated
Starkfeldinduzierte Plasmaerzeugung in dielektrischen Festkörpern
de
refubium.affiliation
Physik
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free
dcterms.accessRights.openaire
open access
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accept