Control of the Polarization of a Vacuum-Ultraviolet, High-Gain, Free-Electron Laser

Enrico Allaria , Bruno Diviacco , Carlo Callegari (1) , Paola Finetti (2) , Benoît Mahieu , Jens Viefhaus , Marco Zangrando (3) , Giovanni de Ninno (4, 5) , Guillaume Lambert (6) , Eugenio Ferrari , Jens Buck , Markus Ilchen , Boris Vodungbo (7) , Nicola Mahne (8) , Cristian Svetina (9) , Carlo Spezzani (10) , Simone Di Mitri , Giuseppe Penco (11) , Mauro Trovó , William M. Fawley , Primoz R. Rebernik , David Gauthier (12) , Cesare Grazioli , Marcello Coreno (13) , Barbara Ressel , Antti Kivimäki (14) , Tommaso Mazza , Leif Glaser , Frank Scholz (15) , Joern Seltmann (16) , Patrick Gessler , Jan Grünert (17) , Alberto de Fanis (18) , Michael Meyer , André Knie (19) , Stefan P. Moeller (20) , Lorenzo Raimondi , Flavio Capotondi (21, 22) , Emanuele Pedersoli , Oksana Plekan , Miltcho B. Danailov , Alexander Demidovich , Ivaylo Nikolov (23, 24) , Alessandro Abrami , Julien Gautier (25) , Jan Lüning (26) , Philippe Zeitoun (7) , Luca Giannessi (27)

1 Sincrotrone Trieste
2 CRCM - Centre de Recherche en Cancérologie de Marseille
3 Laboratorio TASC
4 Sincrotrone Trieste
5 School of Applied Sciences
6 LASA - Laboratoire de Sociologie et d'Anthropologie - UFC (UR 3189)
7 LOA - Laboratoire d'optique appliquée
8 IOM - CNR Istituto Officina dei Materiali
9 Synchrotron ELETTRA
10 Elettra Sincrotrone Trieste
11 Infectious Diseases
12 EDF - EDF
13 CNR-IMIP
14 Laboratorio TASC
15 Institute for Forest Genetics and Forest Tree Breeding
16 German Weather Service
17 European XFEL GmbH
18 Institute of Multidisciplinary Research for Advanced Materials
19 Institute of Physics and CINSaT
20 CMRR - Center for Magnetic Resonance Research [Minneapolis]
21 INFM - NEST-INFM
22 Dipartimento di Scienze Fisiche, Informatiche e Matematiche [Modena]
23 Institute of Psychological Medicine and Clinical Neurosciences
24 MRC Centre for Neuropsychiatric Genetics and Genomics
25 CRC - Centre de Recherche des Cordeliers
26 LCPMR - Laboratoire de Chimie Physique - Matière et Rayonnement
27 ENEA - Italian National agency for new technologies, Energy and sustainable economic development [Frascati]

The two single-pass, externally seeded free-electron lasers (FELs) of the FERMI user facility are designed around Apple-II-type undulators that can operate at arbitrary polarization in the vacuum ultraviolet-to-soft x-ray spectral range. Furthermore, within each FEL tuning range, any output wavelength and polarization can be set in less than a minute of routine operations. We report the first demonstration of the full output polarization capabilities of FERMI FEL-1 in a campaign of experiments where the wavelength and nominal polarization are set to a series of representative values, and the polarization of the emitted intense pulses is thoroughly characterized by three independent instruments and methods, expressly developed for the task. The measured radiation polarization is consistently >90% and is not significantly spoiled by the transport optics; differing, relative transport losses for horizontal and vertical polarization become more prominent at longer wavelengths and lead to a non-negligible ellipticity for an originally circularly polarized state. The results from the different polarimeter setups validate each other, allow a cross-calibration of the instruments, and constitute a benchmark for user experiments.

Domains: Physics [physics]; Physics [physics]; Physics [physics]; Accelerator Physics [physics.acc-ph]; Physics [physics]; Physics [physics]; Optics [physics.optics]; Physics [physics]; Physics [physics]; Plasma Physics [physics.plasm-ph]

Enrico Allaria, Bruno Diviacco, Carlo Callegari, Paola Finetti, Benoît Mahieu, et al.. Control of the Polarization of a Vacuum-Ultraviolet, High-Gain, Free-Electron Laser. European Physical Education Review, 2014, 4 (4), pp.041040. ⟨10.1103/PhysRevX.4.041040⟩. ⟨hal-01163727⟩