This study reports on the physical and optical characterization of scandium oxide thin films. Thin films of scandium oxide, 20-40 nm thick, were deposited on silicon wafers, quartz slides, and silicon photodiodes by reactively sputtering scandium in an oxygen environment. These samples were characterized using ellipsometry, high-resolution transmission electron microscopy, scanning transmission electron microscopy, and energy dispersive x-ray analysis. A 28.46 nm thick scandium oxide thin film was measured in the Extreme Ultraviolet (EUV) from 2.7 to 50 nm (459.3 to 24.8 eV) using synchrotron radiation at the Advanced Light Source Beamline 6.3.2 at the Lawrence Berkeley National Laboratory. In these measurements, a new method for data collection was used, in which the reflection and transmission data were collected simultaneously. Analysis of the EUV reflection and transmission data was performed using a front-side reflection, matrix-multiplication technique, which is novel among EUV analytical practice. During data analysis, a new weighting scheme was used, named "adaptive weighting". This analysis provides the first experimentally determined optical constants n and k for scandium oxide thin films from 4.5-30 nm. Also, the positions of the L2 and L3 electronic transitions of scandium oxide have been measured, at 3.069 and 3.101 nm (404.0 and 399.9 eV), respectively, while the measurements near the M transition suggest it to be at approximately 31.5 nm (39.4 eV). Comparing the electronic transition positions of scandium oxide to those of scandium show that the oxidation of scandium shifts the positions to lower energies. For L2 the shift is about 1.8 eV, for L3 the shift is about 1.4 eV, and for M the shift is about 1.9 eV. The binding energies of scandium oxide are greater than those of scandium, as is expected for an oxide compared to its parent metal. This trend in the shift of the transition positions is unexpected, and warrants further investigation.

This thesis investigates the use of high-power lasers for synchrotron radiation sources with high brilliance, from the EUV to the hard X-ray spectral range. Hereby lasers accelerate electrons by laser-wakefield acceleration (LWFA), act as optical undulators, or both. Experimental evidence shows for the first time that LWFA electron bunches are shorter than the driving laser and have a length scale comparable to the plasma wavelength. Furthermore, a first proof of principle experiment demonstrates that LWFA electrons can be exploited to generate undulator radiation. Building upon these experimental findings, as well as extensive numerical simulations of Thomson scattering, the theoretical foundations of a novel interaction geometry for laser-matter interaction are developed. This new method is very general and when tailored towards relativistically moving targets not being limited by the focusability (Rayleigh length) of the laser, while it does not require a waveguide. In a theoretical investigation of Thomson scattering, the optical analogue of undulator radiation, the limits of Thomson sources in scaling towards higher peak brilliances are highlighted. This leads to a novel method for generating brilliant, highly tunable X-ray sources, which is highly energy efficient by circumventing the laser Rayleigh limit through a novel traveling-wave Thomson scattering (TWTS) geometry. This new method suggests increases in X-ray photon yields of 2-3 orders of magnitudes using existing lasers and a way towards efficient, optical undulators to drive a free-electron laser. The results presented here extend far beyond the scope of this work. The possibility to use lasers as particle accelerators, as well as optical undulators, leads to very compact and energy efficient synchrotron sources. The resulting monoenergetic radiation of high brilliance in a range from extreme ultraviolet (EUV) to hard X-ray radiation is of fundamental importance for basic research, medical applications, material and life sciences and is going to significantly contribute to a new generation of radiation sources and free-electron lasers (FELs).

Die vorliegende Arbeit beschäftigt sich in Experiment und Theorie mit Laser-Plasma beschleunigten Elektronen und optischen Undulatoren zur Erzeugung von brillianter Synchrotronstrahlung. Zum ersten Mal wird experimentell nachgewießen, dass laserbeschleunigte Elektronenpulse kürzer als 30 fs sind. Ferner werden solche Elektronenpulse erstmalig in einem Demonstrationsexperiment durch einen magnetischen Undulator als Synchrotronstrahlenquelle genutzt. Aufbauend auf diesen experimentellen Erkenntnissen, sowie umfangreichen numerischen Simulationen zur Thomsonstreuung, werden die theoretischen Grundlagen einer neuartigen Interaktionsgeometrie für Laser-Materie Wechselwirkungen entwickelt. Diese neue, in der Anwendbarkeit sehr allgemeine Methode basiert auf raum-zeitlicher Laserpulsformung durch nichtlineare Winkeldispersion wie diese durch VLS- (varied-line spacing) Gitter erzeugt werden kann und hat den Vorteil nicht durch die Fokussierbarkeit des Lasers (Rayleighlänge) begrenzt zu sein. Zusammen mit laserbeschleunigten Elektronen ermöglicht dieser traveling-wave Thomson scattering (TWTS) benannte Ansatz neuartige, nur auf optischer Technologie basierende Synchrotronstrahlenquellen mit Zentimeter bis Meter langen optische Undulatoren. Die hierbei mit existierenden Lasern erzielbaren Brillianzen übersteigen diese bestehender Thomsonquellen-Designs um 2-3 Größenordnungen. Die hier vorgestellten Ergebnisse weisen weit über die Grenzen der vorliegenden Arbeit hinaus. Die Möglichkeit Laser als Teilchenbeschleuniger und auch optischen Undulator zu verwenden führt zu bauartbedingt sehr kompakten und energieeffizienten Synchrotronstrahlungsquellen. Die hieraus resultierende monochromatische Strahlung hoher Brillianz in einem Wellenlängenbereich von extremen ultraviolett (EUV) zu harten Röntgenstrahlen ist für die Grundlagenforschung, medizinische Anwendungen, Material- und Lebenswissenschaften von fundamentaler Bedeutung und wird maßgeblich zu einer neuen Generation ultrakurzer Strahlungsquellen und freien Elektronenlasern (FELs) beitragen. / This thesis investigates the use of high-power lasers for synchrotron radiation sources with high brilliance, from the EUV to the hard X-ray spectral range. Hereby lasers accelerate electrons by laser-wakefield acceleration (LWFA), act as optical undulators, or both. Experimental evidence shows for the first time that LWFA electron bunches are shorter than the driving laser and have a length scale comparable to the plasma wavelength. Furthermore, a first proof of principle experiment demonstrates that LWFA electrons can be exploited to generate undulator radiation. Building upon these experimental findings, as well as extensive numerical simulations of Thomson scattering, the theoretical foundations of a novel interaction geometry for laser-matter interaction are developed. This new method is very general and when tailored towards relativistically moving targets not being limited by the focusability (Rayleigh length) of the laser, while it does not require a waveguide. In a theoretical investigation of Thomson scattering, the optical analogue of undulator radiation, the limits of Thomson sources in scaling towards higher peak brilliances are highlighted. This leads to a novel method for generating brilliant, highly tunable X-ray sources, which is highly energy efficient by circumventing the laser Rayleigh limit through a novel traveling-wave Thomson scattering (TWTS) geometry. This new method suggests increases in X-ray photon yields of 2-3 orders of magnitudes using existing lasers and a way towards efficient, optical undulators to drive a free-electron laser. The results presented here extend far beyond the scope of this work. The possibility to use lasers as particle accelerators, as well as optical undulators, leads to very compact and energy efficient synchrotron sources. The resulting monoenergetic radiation of high brilliance in a range from extreme ultraviolet (EUV) to hard X-ray radiation is of fundamental importance for basic research, medical applications, material and life sciences and is going to significantly contribute to a new generation of radiation sources and free-electron lasers (FELs).

This thesis investigates the use of high-power lasers for synchrotron radiation sources with high brilliance, from the EUV to the hard X-ray spectral range. Hereby lasers accelerate electrons by laser-wakefield acceleration (LWFA), act as optical undulators, or both. Experimental evidence shows for the first time that LWFA electron bunches are shorter than the driving laser and have a length scale comparable to the plasma wavelength. Furthermore, a first proof of principle experiment demonstrates that LWFA electrons can be exploited to generate undulator radiation. Building upon these experimental findings, as well as extensive numerical simulations of Thomson scattering, the theoretical foundations of a novel interaction geometry for laser-matter interaction are developed. This new method is very general and when tailored towards relativistically moving targets not being limited by the focusability (Rayleigh length) of the laser, while it does not require a waveguide. In a theoretical investigation of Thomson scattering, the optical analogue of undulator radiation, the limits of Thomson sources in scaling towards higher peak brilliances are highlighted. This leads to a novel method for generating brilliant, highly tunable X-ray sources, which is highly energy efficient by circumventing the laser Rayleigh limit through a novel traveling-wave Thomson scattering (TWTS) geometry. This new method suggests increases in X-ray photon yields of 2-3 orders of magnitudes using existing lasers and a way towards efficient, optical undulators to drive a free-electron laser. The results presented here extend far beyond the scope of this work. The possibility to use lasers as particle accelerators, as well as optical undulators, leads to very compact and energy efficient synchrotron sources. The resulting monoenergetic radiation of high brilliance in a range from extreme ultraviolet (EUV) to hard X-ray radiation is of fundamental importance for basic research, medical applications, material and life sciences and is going to significantly contribute to a new generation of radiation sources and free-electron lasers (FELs).

Ni80Fe20 and Ni80Fe20/NiO films and nano-stripes were characterized magnetically through AC and DC susceptibility measurements, and hysteresis loops as a function of field and temperature. While the near-pattern films were characterized in the in-plane configuration only, the nano-stripes were characterized in parallel, transverse and the perpendicular field configurations. The effects of the constrained geometry on the coercivity, exchange bias field, and the superparamagnetic blocking temperature were studied. It was determined that the coercivity, exchange bias field and the superparamagnetic blocking temperature can be controlled, not only by using a patterned media instead of a plane film, but also by the orientation of that pattern.

Ni80Fe20 and Ni80Fe20/NiO films and nano-stripes were characterized magnetically through AC and DC susceptibility measurements, and hysteresis loops as a function of field and temperature. While the near-pattern films were characterized in the in-plane configuration only, the nano-stripes were characterized in parallel, transverse and the perpendicular field configurations. The effects of the constrained geometry on the coercivity, exchange bias field, and the superparamagnetic blocking temperature were studied. It was determined that the coercivity, exchange bias field and the superparamagnetic blocking temperature can be controlled, not only by using a patterned media instead of a plane film, but also by the orientation of that pattern.

No description available.

Die vorliegende Arbeit beschäftigt sich in Experiment und Theorie mit Laser-Plasma beschleunigten Elektronen und optischen Undulatoren zur Erzeugung von brillianter Synchrotronstrahlung. Zum ersten Mal wird experimentell nachgewießen, dass laserbeschleunigte Elektronenpulse kürzer als 30 fs sind. Ferner werden solche Elektronenpulse erstmalig in einem Demonstrationsexperiment durch einen magnetischen Undulator als Synchrotronstrahlenquelle genutzt. Aufbauend auf diesen experimentellen Erkenntnissen, sowie umfangreichen numerischen Simulationen zur Thomsonstreuung, werden die theoretischen Grundlagen einer neuartigen Interaktionsgeometrie für Laser-Materie Wechselwirkungen entwickelt. Diese neue, in der Anwendbarkeit sehr allgemeine Methode basiert auf raum-zeitlicher Laserpulsformung durch nichtlineare Winkeldispersion wie diese durch VLS- (varied-line spacing) Gitter erzeugt werden kann und hat den Vorteil nicht durch die Fokussierbarkeit des Lasers (Rayleighlänge) begrenzt zu sein. Zusammen mit laserbeschleunigten Elektronen ermöglicht dieser traveling-wave Thomson scattering (TWTS) benannte Ansatz neuartige, nur auf optischer Technologie basierende Synchrotronstrahlenquellen mit Zentimeter bis Meter langen optische Undulatoren. Die hierbei mit existierenden Lasern erzielbaren Brillianzen übersteigen diese bestehender Thomsonquellen-Designs um 2-3 Größenordnungen. Die hier vorgestellten Ergebnisse weisen weit über die Grenzen der vorliegenden Arbeit hinaus. Die Möglichkeit Laser als Teilchenbeschleuniger und auch optischen Undulator zu verwenden führt zu bauartbedingt sehr kompakten und energieeffizienten Synchrotronstrahlungsquellen. Die hieraus resultierende monochromatische Strahlung hoher Brillianz in einem Wellenlängenbereich von extremen ultraviolett (EUV) zu harten Röntgenstrahlen ist für die Grundlagenforschung, medizinische Anwendungen, Material- und Lebenswissenschaften von fundamentaler Bedeutung und wird maßgeblich zu einer neuen Generation ultrakurzer Strahlungsquellen und freien Elektronenlasern (FELs) beitragen. / This thesis investigates the use of high-power lasers for synchrotron radiation sources with high brilliance, from the EUV to the hard X-ray spectral range. Hereby lasers accelerate electrons by laser-wakefield acceleration (LWFA), act as optical undulators, or both. Experimental evidence shows for the first time that LWFA electron bunches are shorter than the driving laser and have a length scale comparable to the plasma wavelength. Furthermore, a first proof of principle experiment demonstrates that LWFA electrons can be exploited to generate undulator radiation. Building upon these experimental findings, as well as extensive numerical simulations of Thomson scattering, the theoretical foundations of a novel interaction geometry for laser-matter interaction are developed. This new method is very general and when tailored towards relativistically moving targets not being limited by the focusability (Rayleigh length) of the laser, while it does not require a waveguide. In a theoretical investigation of Thomson scattering, the optical analogue of undulator radiation, the limits of Thomson sources in scaling towards higher peak brilliances are highlighted. This leads to a novel method for generating brilliant, highly tunable X-ray sources, which is highly energy efficient by circumventing the laser Rayleigh limit through a novel traveling-wave Thomson scattering (TWTS) geometry. This new method suggests increases in X-ray photon yields of 2-3 orders of magnitudes using existing lasers and a way towards efficient, optical undulators to drive a free-electron laser. The results presented here extend far beyond the scope of this work. The possibility to use lasers as particle accelerators, as well as optical undulators, leads to very compact and energy efficient synchrotron sources. The resulting monoenergetic radiation of high brilliance in a range from extreme ultraviolet (EUV) to hard X-ray radiation is of fundamental importance for basic research, medical applications, material and life sciences and is going to significantly contribute to a new generation of radiation sources and free-electron lasers (FELs).

Im Idealfall bilden die Kopenhagener Kriterien zusammen mit dem Art.-7-Verfahren EUV einen lückenlosen Schutzmechanismus der EU-Werte. Die Verfassungskrisen in Ungarn und Polen haben allerdings nicht nur die Schwächen des Art.-7-Verfahren aufgedeckt, sondern auch die Frage aufgeworfen, ob die gegenwärtige Anwendungsweise des Kopenhagener Mechanismus ausreichend ist. Da das Beitrittsverfahren an sich Regierung-zentrisch ist, ist es offenkundig, dass dieses Verfahren nicht viel dazu beiträgt, die Bürger in den politischen Prozess ihres Landes einzubinden und die Zivilgesellschaft zu stärken. Es dauert eine gewisse Zeit, bis die konstitutionelle Grundwerte in die Herzen der Bürger eines neulich demokratisierten Landes gebracht werden. Die EU wurde allerdings dadurch unter Zeitdruck gesetzt, dass sie die Osterweiterung in einem relativ kurzen Zeitraum vollenden musste, um die Gunst der Stunde für ein vereintes Europa nutzen können. Der aktuellen Zustand der EU entspricht dem echten Bund im Schmittschen Sinn. Die Substanz der Homogenität in einem echten Bund ist das Produkt des Zusammenspiels der Verfassungsordnung des Bundes und seiner Mitglieder. Daraus ergibt sich, dass mit jedem Beitritt eines neuen Mitgliedstaats die Verfassungsidentität der EU mit einer neuen Verfassungsidentität angereichert und wesentlich geändert wird. Wenn man die Eingriffskapazität der EU in die innerstaatlichen Verfassungsordnungen über die heutige Intensität hinaus noch verstärken will, darf man die politische Natur der Werte-Frage in einem echten Bund nicht außer Acht lassen. Der Priorisierung der politischen Kriterien vor den wirtschaftlichen Kriterien, mit der die EU die Beitrittsverhandlungen durchgeführt hat, ist für Taiwans China-Politik ebenso wichtig. Eine entscheidende Aufgabe für Taiwan ist, klar zu machen, dass Taiwan politische Verhandlungen nur mit einem Ansprechpartner führen wird, der die gleichen politischen Werte einhält. / In the course of developing a general theory aiming at reversing and preventing the deterioration of political values in the European and East-Asian context, this study answered two sets of questions. First, on the empirical level, how reasonable and effective are the current pre-accession evaluations? Regarding the existing deterioration in the post-accession context, does it reflect any short coming in the way the EU implements the Copenhagen Criteria? Since Taiwan has not established such monitoring mechanism yet, what are the damages already done to Taiwan’s constitutional values? Second, on the normative level, this study followed two very different approaches. On the one hand, it clarified where the limits of judicial solution to this problem are. The fact that the sanction procedures prescribed in the current Art. 7 TEU take the form of collective actions revealed that what is at stake here is a shared value system. On the other hand, this study took into account the interaction between law and politics. The accession of new member states, as well the sanction against member states which failed to respect the political values of the Union, are in essence political decisions of the European Union. Since Taiwan needs to set up political conditions for it negotiations with China, the task is highly political, too. By identifying elements that caused or prevented the deterioration of political values, this study proposed suggestions for correcting and preventing deterioration by understanding its operation. A protective mechanism for Taiwan’s political values can create a reverse “lock-in effect.” By enunciating stringent negotiation guidelines and a code of conduct for Taiwanese government that requires cautiousness and vigilance, this mechanism will place the cross-strait negotiations under a legal framework which ensures that any given Taiwanese government could not sacrifice Taiwan’s constitutional values in exchange for advancing its political agenda.

Le domaine du rayonnement extrême ultraviolet (EUV) offre de grandes possibilités scientifiques et technologiques en photolithographie, en astrophysique, en spectrométrie de photoélectron, etc. Ainsi, de nombreux miroirs multicouches sont développés pour fonctionner dans ce domaine spectral, qui joue un rôle important pour les applications optiques. L'objectif de ce travail est de concevoir, réaliser, caractériser et proposer des multicouches (Mg/Co, Al/SiC, ...). Puis le but est d'appliquer une méthode capable de distinguer entre interdiffusion et rugosité géométrique afin de corréler les performances optiques de la multicouche à sa qualité structurale. Nous proposons de caractériser les miroirs multicouches en employant une méthodologie combinant plusieurs techniques (Spectroscopie d'émission X, Réflectométrie EUV, ...). La combinaison de ces méthodes permet d'obtenir une description chimique et structurale de l'empilement multicouche et de comprendre les phénomènes prenant place aux interfaces. Il est en effet important de connaître les phénomènes interfaciaux, comme la formation de composés ou le développement de la rugosité, car ils gouvernent les propriétés optiques des multicouches.