Optische Frequenzkonversion in optisch nichtlinearen, polymeren Wellenleitern mit Quasiphasenanpassung

Frequenzverdopplungsmodule bestehend aus quasiphasenangepaßten NLO-Wellenleitern wurden photolithographisch hergestellt und charakterisiert. Dies beinhaltet sowohl die Auswahl, Herstellung und Charakterisierung der NLO-Polymere hinsichtlich ihrer Eignung zur Frequenzkonversion als auch die Auswahl, Herstellung und Charakterisierung von Wellenleiterstrukturen. Die Tensorkomponenten der optisch nichtlinearen Suszeptibilität von NLO-Polymeren mit Dispersionsrot (DR1) und Cyanobiphenyl (CN) als NLO-Moleküle in Polymethylmethacrylat eingemischt bzw. über flexiblen Spacer an das Polymerrückgrat angebunden wurden durch polarisations- und vom Einfallswinkel abhängige SH-Messungen bestimmt. Der optisch nichtlineare Koeffizient des Cyanobiphenyl-Seitenkettenpolymers ist 12pm/V, der des Dispersionsrot-Seitenkettenpolymers 85pm/V. Dabei ist die Orientierung der optisch nichtlinearen Moleküle in der Polymermatrix durch Koronaentladung über der Polymeroberfläche der Polung mittels Kontaktelektroden deutlich überlegen. Im direkten Vergleich zeigten koronagepolte NLO-Polymerschichten eine 18-fach größere feldinduzierte SH-Intensität. Für das Design der Frequenzverdopplungsmodule wurden verschiedene Wellenleiterkonzepte zunächst numerisch hinsichtlich ihrer Eignung zur Frequenzkonversion untersucht. Das Rippenwellenleiterkonzept wurde in der vorliegenden Arbeit erstmalig für die Frequenzkonversion realisiert. Hierzu wurden 4" SiO2-Wafer mit einer Einbettungsschicht versehen, anschließend mit Photoresist maskiert und photolithographisch strukturiert, die Gräben eingebracht und abschließend mit dem NLO-Polymer verfüllt. Die Kopplungsdämpfung lag bei 3db. Die Dämpfung in den CN-Rippenwellenleitern liegt bei 3db für die Grundwelle und bei 2db für die 2-te Harmonische, in den DR1-Rippenwellenleitern bei 10db und 100db. Eine neue Methode zur Realisierung der Quasiphasenanpassung in Wellenleitern wurde im Rahmen der vorliegenden Arbeit entwickelt und demonstriert. Durch die Orientierung der NLO-Moleküle in der Führungsschicht mittels einer fächerartig periodisch modulierten Oberfläche konnte erstmalig eine Abstimmung der SH-Intensität über eine variable QPM-Periode demonstriert werden. In Schichtwellenleitern mit dem Cyanobiphenyl-Guest-Host-Polymer als Führungsschicht wurde eine Konversionseffizienz von 0.005%/W erzielt. Unter Ausnutzung der Quasiphasenanpassung 2-ter Ordnung konnten in 1.5mm langen Dispersionsrot-Schichtwellenleitern vergleichbare SH-Effizienzen erreicht werden. Der höchste Wirkungsgrad wurde in Rippenwellenleitern mit dem Cyanobiphenyl-Guest-Host-Polymer als optisch nichtlineare Führungsschicht erzielt: 0.024%/W

Assessing complex PTSD and PTSD: validation of the German version of the International Trauma Interview (ITI)

Background: With the introduction of the ICD-11 into clinical practice, the reliable distinction between Posttraumatic Stress Disorder (PTSD) and Complex Posttraumatic Stress Disorder (CPTSD) becomes paramount. The semi-structured clinician-administered International Trauma Interview (ITI) aims to close this gap in clinical and research settings. Objective: This study investigated the psychometric properties of the German version of the ITI among trauma-exposed clinical samples from Switzerland and Germany. Method: Participants were 143 civilian and 100 military participants, aged M = 40.3 years, of whom 53.5% were male. Indicators of reliability and validity (latent structure, internal reliability, inter-rater agreement, convergent and discriminant validity) were evaluated. Confirmatory factor analysis (CFA) and partial correlation analysis were conducted separately for civilian and military participants. Results: Prevalence of PTSD was 30% (civilian) and 33% (military) and prevalence of CPTSD was 53% (civilians) and 21% (military). Satisfactory internal consistency and inter-rater agreement were found. In the military sample, a parsimonious first-order six-factor model was preferred over a second-order two-factor CFA model of ITI PTSD and Disturbances in Self-Organization (DSO). Model fit was excellent among military participants but no solution was supported among civilian participants. Overall, convergent validity was supported by positive correlations of ITI PTSD and DSO with DSM-5 PTSD. Discriminant validity for PTSD symptoms was confirmed among civilians but low in the military sample. Conclusions: The German ITI has shown potential as a clinician-administered diagnostic tool for assessing ICD-11 PTSD and CPTSD in primary care. However, further exploration of its latent structure and discriminant validity are indicated

New perspectives for research of matter at extreme conditions : the high-energy density instrument at the European XFEL

Free-electron lasers (FELs) produce extremely intense, coherent and ultrashort pulses of light. Due to these properties, FELs can be used to investigate electronic and structural properties of short lived systems at very high spatial and temporal resolution and thus open up completely new scientific applications. From 2017 onwards, the European X-ray Free Electron Laser (XFEL) in Hamburg, Germany will provide hard and soft X-ray FEL radiation. This facility will be operated as a user facility providing access to a wide user community. The High-Energy Density science instrument (HED) is one of the six baseline instruments at the European XFEL. It is dedicated to the study of dense and highly driven matter. For such excitation either the FEL, various types of optical lasers (OLs) or pulsed magnetic fields will be available. Located on the SASE2 FEL undulator, hard X-rays with energies between 5 and 25 keV, a photon flux of about $10^{12}$ photons/pulse at 12 keV photon energy, a pulse duration of 2 - 100 fs and a repetition rate of up to 4.5 MHz will be available for experiments. The HED instrument is currently in its technical design phase. First user experiments are foreseen for 2017. The X-ray beam transport at HED is based on the use of mirrors, compound refractive Be lenses and crystal monochromators. X-ray beam sizes on the sample will range from few μm to 200 μm. The relative energy resolutions can be chosen to be ~$10^{-3}$, $10^{-4}$ or $10^{-6}$. A hard X-ray split-and-delay unit will provide a sequence of two X-ray pulses to excite and probe a sample with delays between the pulses of up to 23 - 2 ps in the energy range of 5 – 20 keV, respectively. Three OL systems are planned at the HED instrument for driving samples into extreme states. A high-repetition rate system, matching the X-ray delivery pattern, can provide up to 100 mJ pulse energies. A 10 Hz 100 TW-class ultrahigh-intensity OL does reach focused intensities beyond $10^{19}$ $W/cm^{2}$, allowing the study of relativistic laser-matter interactions. For the studies of planetary matter, a 10 Hz 100 J class high-energy OL will be available. It is furthermore planned to provide magnetic fields with up to ~50 T for magnetic scattering experiments. The two high energy OLs and the pulsed magnet setup will be provided by the HIBEF user consortium. The X-ray split-and-delay unit will be build by the University Münster (BMBF-05K10PM2 and -05K13PM1). In this contribution, we discuss prototype hard-condensed matter experiments in the field of planetary research. These include optical laser induced quasi-isentropic (ramped) compression and shock compression experiments and diamond anvil cell experiments

Studying planetary matter using intense x-ray pulses

Free-electron laser facilities enable new applications in the field of high-pressure research including planetary materials. The European x-ray Free Electron Laser (European XFEL) in Hamburg, Germany will start user operation in 2017 and will provide photon energies of up to 25 keV. The high-energy density science instrument (HED) is one of the six baseline instruments at the European XFEL. It is dedicated to the study of dense material at strong excitation in a temperature range from eV to keV and pressures >100 GPa which is equivalent to an energy density >100 J mm$^{−3}$. It will enable studying structural and electronic properties of excited states with hard x-rays. The instrument is currently in its technical design phase and first user experiments are foreseen for summer 2017. In this contribution, we present the x-ray instrumentation and foreseen x-ray techniques at HED and concentrate on prototype hard-condensed matter experiments in the field of planetary research as proposed during recent user consortium meetings for this instrument. These include quasi-isentropic (ramped) compression and shock compression experiments

The High Energy Density science instrument at the European XFEL, Hamburg, Germany: a new platform for shock compression research

Free-electron laser facilities enable new applications in the field of high-pressure research including geo- and planetary sciences. At the European X-ray Free Electron Laser (XFEL) in Hamburg, one of the six baseline instruments is dedicated to High Energy Density Science (HED). A 100 J optical laser with nanosecond pulse duration, high repetition rate and pulse shaping option will be integrated at this instrument, which will allow to shock compressing matter to very high internal pressures of up to 1 TPa and to off-Hugoniot states at lower pressures with ramped compression. This will enable to mimic conditions similar to the interior of Saturn, Neptune, Uranus, Earth and Venus. The extreme states of matter can then be probed with the FEL X-ray source. At European XFEL hard X-rays with photon energies of up to 25 keV will be available. At the HED instrument, several X-ray techniques will be realized to probe the samples such as X-ray diffraction, X-ray imaging and spectroscopy including XANES. The high intensity and time structure of the FEL beam will enable time-resolved pump-probe studies of the samples generated during dynamic compression. The envisaged instrument time resolution is in the range of a few 10s fs which is well below the time scales of phase transitions. In addition, the high brilliance and coherence of the FEL radiation will allow spatially resolved studies. The HED instrument is currently in its detailed design phase and first user operation is foreseen for late 2017. In this contribution, we will present the capabilities of the HED instrument with respect to geo- and planetary sciences, compare this to state-of-the-art in-situ techniques and will show planned first experiments of this instrument

Perspectives for studying planetary matter using intense X-ray pulses at the high energy density science instrument at the European XFEL

Free-electron laser facilities enable new applications in the field of high-pressure research including planetary materials. The European X-ray Free Electron Laser (European XFEL) in Hamburg, Germany will start user operation in 2017 and will provide photon energies of up to 25 keV. The high-energy density science instrument (HED) at the European XFEL is dedicated to the study of dense material at strong excitation in a temperature range from eV to keV and pressures > 100 GPa which is equivalent to an energy density > 100 J/mm$^{3}$. It will enable studying structural and electronic properties of excited states with hard X-rays at a repetition rate of up to 4.5 MHz. The instrument is currently in its technical design phase and first user experiments are foreseen for end of 2017. In this contribution, we present the X-ray instrumentation and the foreseen X-ray techniques at HED. In addition, we discuss prototype hard-condensed matter experiments in the field of planetary research as proposed during recent user consortium meetings for this instrument. These include optical laser induced quasiisentropic (ramped) compression and shock compression experiments and diamond anvil cell experiments

The High Energy Density (HED) science instrument at European XFEL: a new platform to experimentally study planetary matter

The High Energy Density science instrument (HED) at the European XFEL, Hamburg, Germany will provide unique experimental possibilities for the investigation of near solid material driven to extreme states and will also establish a new platform to study materials response to shock compression. HED is located at the SASE2 undulator, which provides up to 27000 pulses per second with about $10^{12}$ photons per pulse, photon energies between 3 and 24 keV and pulse lengths of 2 – 100 fs. Self-seeding is foreseen, as well as natural bandwidth (BW) SASE radiation. In addition, energy BW of $10^{-4}$ and $10^{-6}$ will be available through monochromators. Focussing is based on CRL optics, which will allow to provide beam sizes of 2 μm, 10-20 μm and 150 – 260 μm at the sample position. Samples will be driven to extreme states by different types of optical lasers (either 200 kHz/3 mJ/15 fs, 10 Hz/100 TW/30 fs or 10 Hz/100J/ns), the pump-probe FEL beam (delays of up to 2 -23 ps for 5 -20 keV using a split-and-delay unit) and pulsed magnetic fields (up to 50 T). Pump probe experiments can be performed at adapted repetition rates (4.5 MHz, 1 – 10 Hz, single shot). X-ray techniques comprise diffraction, imaging and spectroscopic methods. User operation is planned for fall 2017. We will present the science case of HED, the current layout and present ideas on first shock compression experiment

Technical Design Report: Scientific Instrument High Energy Density Physics (HED)

This technical design report (TDR) of the High Energy Density Physics scientific instrument (HED instrument) at the European XFEL outlines the scientific and technological requirements for the various subsystems and describes the technical realization of the instrument chosen to match these requirements.The scientific requirements have been extracted from a range of proposed scientific applications at HED. Most of these applications had been discussed in the past years as the core of the scientific activity at HED, but, with the recent start of operation of the Matter under Extreme Conditions instrument at the Linac Coherent Light Source (LCLS) at SLAC National Accelerator Laboratory in Menlo Park, California, several new ideas and applications have been included. High energy density (HED) matter is generally defined as having an energy density above 1011 J•$m^{-3}$, which is equivalent to 100 GPa (1 Mbar) pressure and 500 T magnetic pressure