Constructing and Commissioning HELIOS – A High Harmonic Generation Source for Pump-Probe Measurements with sub 50 fs Temporal Resolution: The Development of Experimental Equipment for Extreme Ultraviolet Spectroscopy
2016 (English)Doctoral thesis, comprehensive summary (Other academic)
This thesis presents HELIOS, an in-house laboratory for time-resolved pump-probe spectroscopy with extreme-ultraviolet (XUV) probe radiation. A wide span of pump wavelengths can be generated using commercial laser equipment while XUV probe radiation is generated via a high harmonic generation process in a noble gas delivering probe photons with energies between 20 eV and 72 eV. The XUV beam path features a time-preserving monochromator and was constructed and built in-house. HELIOS features an overall time resolution of about 50 fs when using 800 nm pump and 41 eV probe photons. An energy resolution of 110 meV at 41 eV photon energy can be achieved. HELIOS features two beamlines. One µ-focus beamline with an XUV focal size of about 20 µm can be used with experiments that require such a small XUV focal size as well as with different end stations. The other beamline features a semi-permanently mounted end station for angle-resolved photoelectron spectroscopy under ultra-high vacuum conditions.
Experiments demonstrating the usability of HELIOS and the two beamlines are presented. A pump-probe measurement on graphene demonstrates the capability of determining a large part of the k-space in only one measurement due to the use of an ARTOF angle-resolved time-of-flight electron spectrometer. A non-angle-resolved pump-probe measurement on the conducting polymer PCPDTBT demonstrates the high signal-to-noise ratio achievable at this beamline in non-angle-resolved photoelectron-spectroscopy pump-probe measurements. The usability of the µ-focus beamline is demonstrated with time-resolved measurements on magnetic samples employing an in-house-designed spectrometer. These experiments allow the retrieval of element-specific information on the magnetization within a sample employing the transversal magneto-optical Kerr effect (T-MOKE).
Additionally, a Fourier transform spectrometer for the XUV is presented, the concept was tested at a synchrotron and it was used to determine the longitudinal coherence of the XUV radiation at HELIOS.
Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2016. , 80 p.
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 1360
Angle-resolved photoemission spectroscopy, Angle resolved photoemission spectroscopy, Angle-resolved time-of-flight, Angle resolved time of flight, ARTOF, ARPES, tr-ARPES, fs, fs resolution, Fourier transform spectrometer, Fourier-transform spectrometer, Fourier transform spectroscopy, Fourier-transform spectroscopy, FTS, gas cell, high harmonic generation, laser, liquid jet, monochromator, HELIOS, HHG, off-plane mount, off plane mount, OPA, optical parametric amplifier, PCPDTBT, pulse shaping, pump probe, pump-probe measurements, pump-probe measurements, pump-probe spectroscopy, pump-probe spectroscopy, Rowland spectrometer, time-of-flight spectrometer, time of flight spectrometer, TOF, time-resolved spectroscopy, time resolved spectroscopy, time-resolved experiments, time resolved experiments, T-MOKE, tr-PES, PES, photoelectron spectroscopy, transverse magneto optical Kerr effect, transverse magneto-optical Kerr effect, ultrafast, ultra-high vacuum, ultra high vacuum, UHV, XUV, VUV, X-rays, Permalloy, magnetization dynamic
Accelerator Physics and Instrumentation Atom and Molecular Physics and Optics
Research subject Physics with spec. in Atomic, Molecular and Condensed Matter Physics
IdentifiersURN: urn:nbn:se:uu:diva-281298ISBN: 978-91-554-9528-2OAI: oai:DiVA.org:uu-281298DiVA: diva2:915355
2016-05-17, Häggsalen, Ångströmlaboratoriet, Lägerhyddsvägen 1, Uppsala, 13:15 (English)
Murnane, Margaret, Professor
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