id,collection,dc.contributor.author,dc.contributor.firstReferee,dc.contributor.furtherReferee,dc.contributor.gender,dc.date.accepted,dc.date.accessioned,dc.date.available,dc.date.issued,dc.description.abstract[en],dc.format.extent,dc.identifier.uri,dc.identifier.urn,dc.language,dc.rights.uri,dc.subject.ddc,dc.subject[en],dc.title,dc.title.translated[de],dc.type,dcterms.accessRights.dnb,dcterms.accessRights.openaire,dcterms.accessRights.proquest,dcterms.format,refubium.affiliation "e8347cbc-d943-4239-b7ca-3a4061badd66","fub188/14","Jürgens, Peter","Vrakking, Marc J. J.","Baumert, Thomas","male","2020-12-10","2021-03-26T10:33:02Z","2021-03-26T10:33:02Z","2021","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","v, 143 Seiten","https://refubium.fu-berlin.de/handle/fub188/29788||http://dx.doi.org/10.17169/refubium-29530","urn:nbn:de:kobv:188-refubium-29788-7","eng","http://www.fu-berlin.de/sites/refubium/rechtliches/Nutzungsbedingungen","500 Naturwissenschaften und Mathematik::530 Physik::530 Physik","strong-field ionization||plasma formation||high harmonic generation","Strong-field induced plasma formation in solid dielectrics","Starkfeldinduzierte Plasmaerzeugung in dielektrischen Festkörpern","Dissertation","free","open access","accept","Text","Physik"