title: Generation of circularly polarized radiation from a compact plasma-based extreme ultraviolet light source for tabletop X-ray magnetic circular dichroism studies.
abstract: Generation of circularly polarized light in the extreme ultraviolet (EUV) spectral region (about 25 eV-250 eV) is highly desirable for applications in spectroscopy and microscopy but very challenging to achieve in a small-scale laboratory. We present a compact apparatus for generation of linearly and circularly polarized EUV radiation from a gas-discharge plasma light source between 50 eV and 70 eV photon energy. In this spectral range, the 3p absorption edges of Fe (54 eV), Co (60 eV), and Ni (67 eV) offer a high magnetic contrast often employed for magneto-optical and electron spectroscopy as well as for magnetic imaging. We simulated and designed an instrument for generation of linearly and circularly polarized EUV radiation and performed polarimetric measurements of the degree of linear and circular polarization. Furthermore, we demonstrate first measurements of the X-ray magnetic circular dichroism at the Co 3p absorption edge with a plasma-based EUV light source. Our approach opens the door for laboratory-based, element-selective spectroscopy of magnetic materials and spectro-microscopy of ferromagnetic domains.
authors.affiliation: RWTH Aachen University, Experimental Physics of EUV, Steinbachstraße 15, 52074 Aachen, Germany.
authors.forename: Daniel
authors.initials: D
authors.lastname: Wilson
authors.affiliation: RWTH Aachen University, Experimental Physics of EUV, Steinbachstraße 15, 52074 Aachen, Germany.
authors.forename: Denis
authors.initials: D
authors.lastname: Rudolf
authors.affiliation: Forschungszentrum Jülich GmbH, Peter Grünberg Institut (PGI-6), JARA-FIT, 52425 Jülich, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Weier
authors.affiliation: Forschungszentrum Jülich GmbH, Peter Grünberg Institut (PGI-6), JARA-FIT, 52425 Jülich, Germany.
authors.forename: Roman
authors.initials: R
authors.lastname: Adam
authors.affiliation: Institut für Angewandte Physik, Universität Hamburg, Jungiusstraße 11, 20355 Hamburg, Germany.
authors.forename: Gerrit
authors.initials: G
authors.lastname: Winkler
authors.affiliation: Institut für Angewandte Physik, Universität Hamburg, Jungiusstraße 11, 20355 Hamburg, Germany.
authors.forename: Robert
authors.initials: R
authors.lastname: Frömter
authors.affiliation: RWTH Aachen University, Chair for Technology of Optical Systems, JARA-FIT, Steinbachstraße 15, 52074 Aachen, Germany.
authors.forename: Serhiy
authors.initials: S
authors.lastname: Danylyuk
authors.affiliation: Fraunhofer Institute for Laser Technology, Steinbachstrasse 15, 52074 Aachen, Germany.
authors.forename: Klaus
authors.initials: K
authors.lastname: Bergmann
authors.affiliation: Forschungszentrum Jülich GmbH, Peter Grünberg Institut (PGI-9), JARA-FIT, 52425 Jülich, Germany.
authors.forename: Detlev
authors.initials: D
authors.lastname: Grützmacher
authors.affiliation: Forschungszentrum Jülich GmbH, Peter Grünberg Institut (PGI-6), JARA-FIT, 52425 Jülich, Germany.
authors.forename: Claus M
authors.initials: CM
authors.lastname: Schneider
authors.affiliation: RWTH Aachen University, Experimental Physics of EUV, Steinbachstraße 15, 52074 Aachen, Germany.
authors.forename: Larissa
authors.initials: L
authors.lastname: Juschkin