FEL2013 - List of Keywords (polarization)

Paper	Title	Other Keywords	Page
MOPSO61	Modulated Medium for Generation of Transition Radiation	electron, radiation, dipole, lattice	105
	K.B. Oganesyan ANSL, Yerevan, Armenia
	Funding: ISTC It is shown on an example of amorphous quartz, under the influence of a standing microwave field, at its certain parameters, superlattice is created in the medium where difference in values of dielectric constants of neighboring layers can be up to third order. This superlattice exists during the nanosecond, however it is sufficient for using it as a radiator for generation of transition radiation by relativistic electrons.

TUOANO02	Long-term Stable, Large-scale, Optical Timing Distribution Systems With Sub-femtosecond Timing Stability	laser, feedback, optics, electron	156
	M.Y. Peng, P.T. Callahan, F.X. Kaertner, A.H. Nejadmalayeri MIT, Cambridge, Massachusetts, USA K. Ahmed, S. Valente, M. Xin DESY, Hamburg, Germany P. Battle, T.D. Roberts AdvR, Inc., Montana, USA J.M. Fini, L. Grüner-Nielsen, E. Monberg, M. Yan OFS Laboratories, New Jersey, USA F.X. Kaertner CFEL, Hamburg, Germany
	Funding: US Department of Energy Contract DE-SC0005262 and Center for Free-Electron Laser Science, DESY, Hamburg Sub-fs X-ray pulse generation in kilometer-scale FEL facilities will require sub-fs long-term timing stability between optical sources over kilometer distances. We present here key developments towards a completely fiber-coupled, sub-fs optical timing distribution system. Our approach [] is to lock a femtosecond pulsed laser to a microwave reference and distribute its pulse train through fiber links stabilized by balanced optical cross-correlators (BOCs) []. First, we verified that low-noise optical master oscillators for sub-fs timing distribution are available today; the measured jitter for two commercial femtosecond lasers is less than 70 as for frequencies above 1 kHz. Second, we developed a novel 1.2 km dispersion-compensated, polarization-maintaining fiber link to eliminate drifts induced by polarization mode dispersion. Link stabilization for 16 days showed 0.6 fs RMS timing drift and during a 3-day interval only 0.13 fs drift. Lastly, we fabricated a hybrid-integrated BOC using PPKTP waveguides [*] to eliminate alignment drifts and to reduce the link operation power by a factor of 10-100, which will reduce timing errors induced by fiber nonlinearities. J. Kim et al., Nat. Photon., 2, 12, 733–736, 2008. J. Kim et al., Opt. Lett., 32, 9, 1044–1046, 2007. * A. H. Nejadmalayeri et al., Opt. Lett., 34, 16, 2522–2524, 2009.
	Slides TUOANO02 [1.387 MB]

TUPSO39	Development of a Photo Cathode Laser System for Quasi Ellipsoidal Bunches at PITZ	laser, diagnostics, electron, cathode	303
	M. Krasilnikov, M. Khojoyan, F. Stephan DESY Zeuthen, Zeuthen, Germany A. Andrianov, E. Gacheva, E. Khazanov, S. Mironov, A. Poteomkin, V. Zelenogorsky IAP/RAS, Nizhny Novgorod, Russia E. Syresin JINR, Dubna, Moscow Region, Russia
	Funding: The work is funded by the German Federal Ministry of education and Research, project 05K10CHE “Development and experimental test of a laser system for producing quasi 3D ellipsoidal laser pulses”. Cathode laser pulse shaping is one of the key issues for high brightness photo injector optimization. A flat-top temporal profile of the cylindrical pulses reduces significantly the transverse emittance of space charge dominated beams. As a next step towards further improvement in photo injector performance a 3D pulse shaping is considered. An ellipsoid with uniform photon density is the goal of studies in the frame of a Joint German-Russian Research Group, including the Institute of Applied Physics (Nizhny Novgorod), Joint Institute of Nuclear Research (Dubna) and the Photo Injector test facility at DESY, Zeuthen site (PITZ). The major purpose of the project is the development of a laser system capable of producing 3D quasi ellipsoidal bunches and supporting a bunch train structure close to the European XFEL specifications. The laser pulse shaping is realized using the spatial light modulator technique. The laser pulse shape diagnostics based on a cross-correlator is under development as well. Experimental tests of the new laser system with electron beam production are foreseen at PITZ. First results on the quasi ellipsoidal laser pulse shaping will be reported.

TUPSO52	R&D Towards a Delta-type Undulator for the LCLS	undulator, vacuum, FEL, radiation	348
	H.-D. Nuhn, S.D. Anderson, G.B. Bowden, Y. Ding, G.L. Gassner, Z. Huang, E.M. Kraft, Yu.I. Levashov, F. Peters, F.E. Reese, J.J. Welch, Z.R. Wolf, J. Wu SLAC, Menlo Park, California, USA A.B. Temnykh Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	The LCLS generates linearly polarized, intense, high brightness x-ray pulses from planar fixed-gap undulators. While the fixed-gap design supports a very successful and tightly controlled alignment concept, it provides only limited taper capability (up to 1% through canted pole and horizontal position adjustability) and lacks polarization control. The latter is of great importance for soft x-ray experiments. A new compact undulator design (Delta) has been developed and tested with a 30-cm-long in-vacuum prototype at Cornell University, which adds those missing properties to the LCLS undulator design and is readily adapted to the LCLS alignment concept. Tuning Delta undulators within tight, FEL type tolerances is a challenge due to the fact that the magnetic axis and the magnet blocks are not easily accessible for measurements and tuning in the fully assembled state. An R&D project is underway to install a 3.2-m long out-of-vacuum device in place of the last LCLS undulator, to provide controllable levels of polarized radiation and to develop measurement and tuning techniques to achieve x-ray FEL type tolerances. Presently, the installation of the device is scheduled for August 2013.

WEPSO60	A Method for Obtaining High Degree of Circular Polarization at X-ray FELs	undulator, FEL, radiation, bunching	651
	E. Schneidmiller, M.V. Yurkov DESY, Hamburg, Germany
	Baseline design of many X-ray FEL undulators assumes a planar configuration which results in a linear polarization of SASE FEL radiation. However, many users experiments would profit from using a circularly polarized radiation. As a cheap upgrade one can consider an installation of a helical afterburner, but then one should have an efficient method to suppress linearly polarized background from the main undulator. In this paper we consider a new method for such a suppression which is illustrated with the parameters of the soft X-ray undulator SASE3 of the European X-ray FEL.

THOCNO04	Jitter-free Time Resolved Resonant CDI Experiments Using Two-color FEL Pulses Generated by the Same Electron Bunch	FEL, electron, laser, undulator	753
	M. Zangrando, E. Allaria, F. Bencivenga, F. Capotondi, D. Castronovo, P. Cinquegrana, M.B. Danailov, G. De Ninno, A.A. Demidovich, S. Di Mitri, B. Diviacco, W.M. Fawley, E. Ferrari, L. Fröhlich, L. Giannessi, R. Ivanov, M. Kiskinova, B. Mahieu, N. Mahne, C. Masciovecchio, I. Nikolov, E. Pedersoli, G. Penco, L. Raimondi, C. Serpico, P. Sigalotti, S. Spampinati, C. Spezzani, C. Svetina, M. Trovò Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy G. De Ninno, D. Gauthier University of Nova Gorica, Nova Gorica, Slovenia D. Fausti Università degli Studi di Trieste, Trieste, Italy L. Giannessi ENEA C.R. Frascati, Frascati (Roma), Italy M. Zangrando IOM-CNR, Trieste, Italy
	The generation of two-color FEL pulses by the same electron bunch at FERMI-FEL has opened unprecedented opportunity for jitter-free FEL pump-FEL probe time resolved coherent diffraction imaging (CDI) experiments in order to access spatial aspects in dynamic processes. This possibility was first explored in proof-of-principle resonant CDI experiments using specially designed sample consisting of Ti grating. The measurements performed tuning the energies of the FEL pulses to the Ti M-absorption edge clearly demonstrated the time dependence of Ti optical constants while varying the FEL-pump intensity and probe time delay. The next planned CDI experiments in 2013 will explore transient states in multicomponent nanostructures and magnetic systems, using the controlled linear or circular polarization of the two-color FEL pulses with temporal resolution in the fs to ps range.
	Slides THOCNO04 [8.778 MB]

Paper

Title

Other Keywords

Page

MOPSO61

Modulated Medium for Generation of Transition Radiation

electron, radiation, dipole, lattice

105

K.B. Oganesyan
ANSL, Yerevan, Armenia

Funding: ISTC
It is shown on an example of amorphous quartz, under the influence of a standing microwave field, at its certain parameters, superlattice is created in the medium where difference in values of dielectric constants of neighboring layers can be up to third order. This superlattice exists during the nanosecond, however it is sufficient for using it as a radiator for generation of transition radiation by relativistic electrons.

TUOANO02

Long-term Stable, Large-scale, Optical Timing Distribution Systems With Sub-femtosecond Timing Stability

laser, feedback, optics, electron

156

M.Y. Peng, P.T. Callahan, F.X. Kaertner, A.H. Nejadmalayeri
MIT, Cambridge, Massachusetts, USA
K. Ahmed, S. Valente, M. Xin
DESY, Hamburg, Germany
P. Battle, T.D. Roberts
AdvR, Inc., Montana, USA
J.M. Fini, L. Grüner-Nielsen, E. Monberg, M. Yan
OFS Laboratories, New Jersey, USA
F.X. Kaertner
CFEL, Hamburg, Germany

Funding: US Department of Energy Contract DE-SC0005262 and Center for Free-Electron Laser Science, DESY, Hamburg
Sub-fs X-ray pulse generation in kilometer-scale FEL facilities will require sub-fs long-term timing stability between optical sources over kilometer distances. We present here key developments towards a completely fiber-coupled, sub-fs optical timing distribution system. Our approach [*] is to lock a femtosecond pulsed laser to a microwave reference and distribute its pulse train through fiber links stabilized by balanced optical cross-correlators (BOCs) [**]. First, we verified that low-noise optical master oscillators for sub-fs timing distribution are available today; the measured jitter for two commercial femtosecond lasers is less than 70 as for frequencies above 1 kHz. Second, we developed a novel 1.2 km dispersion-compensated, polarization-maintaining fiber link to eliminate drifts induced by polarization mode dispersion. Link stabilization for 16 days showed 0.6 fs RMS timing drift and during a 3-day interval only 0.13 fs drift. Lastly, we fabricated a hybrid-integrated BOC using PPKTP waveguides [***] to eliminate alignment drifts and to reduce the link operation power by a factor of 10-100, which will reduce timing errors induced by fiber nonlinearities.
* J. Kim et al., Nat. Photon., 2, 12, 733–736, 2008.
** J. Kim et al., Opt. Lett., 32, 9, 1044–1046, 2007.
*** A. H. Nejadmalayeri et al., Opt. Lett., 34, 16, 2522–2524, 2009.

Slides TUOANO02 [1.387 MB]

TUPSO39

Development of a Photo Cathode Laser System for Quasi Ellipsoidal Bunches at PITZ

laser, diagnostics, electron, cathode

303

M. Krasilnikov, M. Khojoyan, F. Stephan
DESY Zeuthen, Zeuthen, Germany
A. Andrianov, E. Gacheva, E. Khazanov, S. Mironov, A. Poteomkin, V. Zelenogorsky
IAP/RAS, Nizhny Novgorod, Russia
E. Syresin
JINR, Dubna, Moscow Region, Russia

Funding: The work is funded by the German Federal Ministry of education and Research, project 05K10CHE “Development and experimental test of a laser system for producing quasi 3D ellipsoidal laser pulses”.
Cathode laser pulse shaping is one of the key issues for high brightness photo injector optimization. A flat-top temporal profile of the cylindrical pulses reduces significantly the transverse emittance of space charge dominated beams. As a next step towards further improvement in photo injector performance a 3D pulse shaping is considered. An ellipsoid with uniform photon density is the goal of studies in the frame of a Joint German-Russian Research Group, including the Institute of Applied Physics (Nizhny Novgorod), Joint Institute of Nuclear Research (Dubna) and the Photo Injector test facility at DESY, Zeuthen site (PITZ). The major purpose of the project is the development of a laser system capable of producing 3D quasi ellipsoidal bunches and supporting a bunch train structure close to the European XFEL specifications. The laser pulse shaping is realized using the spatial light modulator technique. The laser pulse shape diagnostics based on a cross-correlator is under development as well. Experimental tests of the new laser system with electron beam production are foreseen at PITZ. First results on the quasi ellipsoidal laser pulse shaping will be reported.

TUPSO52

R&D Towards a Delta-type Undulator for the LCLS

undulator, vacuum, FEL, radiation

348

H.-D. Nuhn, S.D. Anderson, G.B. Bowden, Y. Ding, G.L. Gassner, Z. Huang, E.M. Kraft, Yu.I. Levashov, F. Peters, F.E. Reese, J.J. Welch, Z.R. Wolf, J. Wu
SLAC, Menlo Park, California, USA
A.B. Temnykh
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

The LCLS generates linearly polarized, intense, high brightness x-ray pulses from planar fixed-gap undulators. While the fixed-gap design supports a very successful and tightly controlled alignment concept, it provides only limited taper capability (up to 1% through canted pole and horizontal position adjustability) and lacks polarization control. The latter is of great importance for soft x-ray experiments. A new compact undulator design (Delta) has been developed and tested with a 30-cm-long in-vacuum prototype at Cornell University, which adds those missing properties to the LCLS undulator design and is readily adapted to the LCLS alignment concept. Tuning Delta undulators within tight, FEL type tolerances is a challenge due to the fact that the magnetic axis and the magnet blocks are not easily accessible for measurements and tuning in the fully assembled state. An R&D project is underway to install a 3.2-m long out-of-vacuum device in place of the last LCLS undulator, to provide controllable levels of polarized radiation and to develop measurement and tuning techniques to achieve x-ray FEL type tolerances. Presently, the installation of the device is scheduled for August 2013.

WEPSO60

A Method for Obtaining High Degree of Circular Polarization at X-ray FELs

undulator, FEL, radiation, bunching

651

E. Schneidmiller, M.V. Yurkov
DESY, Hamburg, Germany

Baseline design of many X-ray FEL undulators assumes a planar configuration which results in a linear polarization of SASE FEL radiation. However, many users experiments would profit from using a circularly polarized radiation. As a cheap upgrade one can consider an installation of a helical afterburner, but then one should have an efficient method to suppress linearly polarized background from the main undulator. In this paper we consider a new method for such a suppression which is illustrated with the parameters of the soft X-ray undulator SASE3 of the European X-ray FEL.

THOCNO04

Jitter-free Time Resolved Resonant CDI Experiments Using Two-color FEL Pulses Generated by the Same Electron Bunch

FEL, electron, laser, undulator

753

M. Zangrando, E. Allaria, F. Bencivenga, F. Capotondi, D. Castronovo, P. Cinquegrana, M.B. Danailov, G. De Ninno, A.A. Demidovich, S. Di Mitri, B. Diviacco, W.M. Fawley, E. Ferrari, L. Fröhlich, L. Giannessi, R. Ivanov, M. Kiskinova, B. Mahieu, N. Mahne, C. Masciovecchio, I. Nikolov, E. Pedersoli, G. Penco, L. Raimondi, C. Serpico, P. Sigalotti, S. Spampinati, C. Spezzani, C. Svetina, M. Trovò
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
G. De Ninno, D. Gauthier
University of Nova Gorica, Nova Gorica, Slovenia
D. Fausti
Università degli Studi di Trieste, Trieste, Italy
L. Giannessi
ENEA C.R. Frascati, Frascati (Roma), Italy
M. Zangrando
IOM-CNR, Trieste, Italy

The generation of two-color FEL pulses by the same electron bunch at FERMI-FEL has opened unprecedented opportunity for jitter-free FEL pump-FEL probe time resolved coherent diffraction imaging (CDI) experiments in order to access spatial aspects in dynamic processes. This possibility was first explored in proof-of-principle resonant CDI experiments using specially designed sample consisting of Ti grating. The measurements performed tuning the energies of the FEL pulses to the Ti M-absorption edge clearly demonstrated the time dependence of Ti optical constants while varying the FEL-pump intensity and probe time delay. The next planned CDI experiments in 2013 will explore transient states in multicomponent nanostructures and magnetic systems, using the controlled linear or circular polarization of the two-color FEL pulses with temporal resolution in the fs to ps range.

Slides THOCNO04 [8.778 MB]