date: 2020-10-04T09:06:40Z pdf:PDFVersion: 1.5 pdf:docinfo:title: Parallel Broadband Femtosecond Reflection Spectroscopy at a Soft X-Ray Free-Electron Laser xmp:CreatorTool: LaTeX with hyperref package access_permission:can_print_degraded: true subject: X-ray absorption spectroscopy (XAS) and the directly linked X-ray reflectivity near absorption edges yield a wealth of specific information on the electronic structure around the resonantly addressed element. Observing the dynamic response of complex materials to optical excitations in pump?probe experiments requires high sensitivity to small changes in the spectra which in turn necessitates the brilliance of free electron laser (FEL) pulses. However, due to the fluctuating spectral content of pulses generated by self-amplified spontaneous emission (SASE), FEL experiments often struggle to reach the full sensitivity and time-resolution that FELs can in principle enable. Here, we implement a setup which solves two common challenges in this type of spectroscopy using FELs: First, we achieve a high spectral resolution by using a spectrometer downstream of the sample instead of a monochromator upstream of the sample. Thus, the full FEL bandwidth contributes to the measurement at the same time, and the FEL pulse duration is not elongated by a monochromator. Second, the FEL beam is divided into identical copies by a transmission grating beam splitter so that two spectra from separate spots on the sample (or from the sample and known reference) can be recorded in-parallel with the same spectrometer, enabling a spectrally resolved intensity normalization of pulse fluctuations in pump?probe scenarios. We analyze the capabilities of this setup around the oxygen K- and nickel L-edges recorded with third harmonic radiation of the free electron laser in Hamburg (FLASH), demonstrating the capability for pump?probe measurements with sensitivity to reflectivity changes on the per mill level. dc:format: application/pdf; version=1.5 pdf:docinfo:creator_tool: LaTeX with hyperref package access_permission:fill_in_form: true pdf:encrypted: false dc:title: Parallel Broadband Femtosecond Reflection Spectroscopy at a Soft X-Ray Free-Electron Laser modified: 2020-10-04T09:06:40Z cp:subject: X-ray absorption spectroscopy (XAS) and the directly linked X-ray reflectivity near absorption edges yield a wealth of specific information on the electronic structure around the resonantly addressed element. Observing the dynamic response of complex materials to optical excitations in pump?probe experiments requires high sensitivity to small changes in the spectra which in turn necessitates the brilliance of free electron laser (FEL) pulses. However, due to the fluctuating spectral content of pulses generated by self-amplified spontaneous emission (SASE), FEL experiments often struggle to reach the full sensitivity and time-resolution that FELs can in principle enable. Here, we implement a setup which solves two common challenges in this type of spectroscopy using FELs: First, we achieve a high spectral resolution by using a spectrometer downstream of the sample instead of a monochromator upstream of the sample. Thus, the full FEL bandwidth contributes to the measurement at the same time, and the FEL pulse duration is not elongated by a monochromator. Second, the FEL beam is divided into identical copies by a transmission grating beam splitter so that two spectra from separate spots on the sample (or from the sample and known reference) can be recorded in-parallel with the same spectrometer, enabling a spectrally resolved intensity normalization of pulse fluctuations in pump?probe scenarios. We analyze the capabilities of this setup around the oxygen K- and nickel L-edges recorded with third harmonic radiation of the free electron laser in Hamburg (FLASH), demonstrating the capability for pump?probe measurements with sensitivity to reflectivity changes on the per mill level. pdf:docinfo:subject: X-ray absorption spectroscopy (XAS) and the directly linked X-ray reflectivity near absorption edges yield a wealth of specific information on the electronic structure around the resonantly addressed element. Observing the dynamic response of complex materials to optical excitations in pump?probe experiments requires high sensitivity to small changes in the spectra which in turn necessitates the brilliance of free electron laser (FEL) pulses. However, due to the fluctuating spectral content of pulses generated by self-amplified spontaneous emission (SASE), FEL experiments often struggle to reach the full sensitivity and time-resolution that FELs can in principle enable. Here, we implement a setup which solves two common challenges in this type of spectroscopy using FELs: First, we achieve a high spectral resolution by using a spectrometer downstream of the sample instead of a monochromator upstream of the sample. Thus, the full FEL bandwidth contributes to the measurement at the same time, and the FEL pulse duration is not elongated by a monochromator. Second, the FEL beam is divided into identical copies by a transmission grating beam splitter so that two spectra from separate spots on the sample (or from the sample and known reference) can be recorded in-parallel with the same spectrometer, enabling a spectrally resolved intensity normalization of pulse fluctuations in pump?probe scenarios. We analyze the capabilities of this setup around the oxygen K- and nickel L-edges recorded with third harmonic radiation of the free electron laser in Hamburg (FLASH), demonstrating the capability for pump?probe measurements with sensitivity to reflectivity changes on the per mill level. pdf:docinfo:creator: Robin Y. Engel, Piter S. Miedema, Diego Turenne, Igor Vaskivskyi, Günter Brenner, Siarhei Dziarzhytski, Marion Kuhlmann, Jan O. Schunck, Florian Döring, Andriy Styervoyedov, Stuart S.P. Parkin, Christian David, Christian Schüßler-Langeheine, Hermann A. Dürr and Martin Beye PTEX.Fullbanner: This is pdfTeX, Version 3.14159265-2.6-1.40.18 (TeX Live 2017/W32TeX) kpathsea version 6.2.3 meta:author: Robin Y. Engel, Piter S. Miedema, Diego Turenne, Igor Vaskivskyi, Günter Brenner, Siarhei Dziarzhytski, Marion Kuhlmann, Jan O. Schunck, Florian Döring, Andriy Styervoyedov, Stuart S.P. Parkin, Christian David, Christian Schüßler-Langeheine, Hermann A. Dürr and Martin Beye trapped: False meta:creation-date: 2020-10-04T09:06:40Z created: 2020-10-04T09:06:40Z access_permission:extract_for_accessibility: true Creation-Date: 2020-10-04T09:06:40Z Author: Robin Y. Engel, Piter S. Miedema, Diego Turenne, Igor Vaskivskyi, Günter Brenner, Siarhei Dziarzhytski, Marion Kuhlmann, Jan O. Schunck, Florian Döring, Andriy Styervoyedov, Stuart S.P. Parkin, Christian David, Christian Schüßler-Langeheine, Hermann A. Dürr and Martin Beye producer: pdfTeX-1.40.18 pdf:docinfo:producer: pdfTeX-1.40.18 pdf:unmappedUnicodeCharsPerPage: 17 Keywords: X-ray absorption spectroscopy; free electron laser; intensity normalization; transmission grating; X-ray reflectivity access_permission:modify_annotations: true dc:creator: Robin Y. Engel, Piter S. Miedema, Diego Turenne, Igor Vaskivskyi, Günter Brenner, Siarhei Dziarzhytski, Marion Kuhlmann, Jan O. Schunck, Florian Döring, Andriy Styervoyedov, Stuart S.P. Parkin, Christian David, Christian Schüßler-Langeheine, Hermann A. Dürr and Martin Beye dcterms:created: 2020-10-04T09:06:40Z Last-Modified: 2020-10-04T09:06:40Z dcterms:modified: 2020-10-04T09:06:40Z title: Parallel Broadband Femtosecond Reflection Spectroscopy at a Soft X-Ray Free-Electron Laser Last-Save-Date: 2020-10-04T09:06:40Z pdf:docinfo:keywords: X-ray absorption spectroscopy; free electron laser; intensity normalization; transmission grating; X-ray reflectivity pdf:docinfo:modified: 2020-10-04T09:06:40Z meta:save-date: 2020-10-04T09:06:40Z pdf:docinfo:custom:PTEX.Fullbanner: This is pdfTeX, Version 3.14159265-2.6-1.40.18 (TeX Live 2017/W32TeX) kpathsea version 6.2.3 Content-Type: application/pdf X-Parsed-By: org.apache.tika.parser.DefaultParser creator: Robin Y. Engel, Piter S. Miedema, Diego Turenne, Igor Vaskivskyi, Günter Brenner, Siarhei Dziarzhytski, Marion Kuhlmann, Jan O. Schunck, Florian Döring, Andriy Styervoyedov, Stuart S.P. Parkin, Christian David, Christian Schüßler-Langeheine, Hermann A. Dürr and Martin Beye dc:subject: X-ray absorption spectroscopy; free electron laser; intensity normalization; transmission grating; X-ray reflectivity access_permission:assemble_document: true xmpTPg:NPages: 8 pdf:charsPerPage: 3092 access_permission:extract_content: true access_permission:can_print: true pdf:docinfo:trapped: False meta:keyword: X-ray absorption spectroscopy; free electron laser; intensity normalization; transmission grating; X-ray reflectivity access_permission:can_modify: true pdf:docinfo:created: 2020-10-04T09:06:40Z