FEL2012 - List of Authors (Gatti, G.)

Paper

Title

Page

Seeding of SPARC-FEL with a Tunable Fibre-based Source

269

N.Y. Joly
University of Erlangen-Nuremberg, Erlangen-Nuremberg, Germany
S. Bielawski
PhLAM/CERCLA, Villeneuve d'Ascq Cedex, France
W. Chang, P. Hölzer, K. Mak, P.St.J. Russell, F. Tani, J.C. Travers
Max Planck Institute for the Science of Light, Erlangen, Germany
F. Ciocci, L. Giannessi, A. Petralia, M. Quattromini
ENEA C.R. Frascati, Frascati (Roma), Italy
M.-E. Couprie, M. Labat, T. Tanikawa
SOLEIL, Gif-sur-Yvette, France
G. De Ninno, B. Mahieu
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
G. Gatti
INFN/LNF, Frascati (Roma), Italy
V. Petrillo
Istituto Nazionale di Fisica Nucleare, Milano, Italy
J.V. Rau
ISM-CNR, Rome, Italy

Instead of seeding a free electron laser in the UV-VUV with a frequency doubled or tripled laser or high order harmonics, here we investigate and present the first results on seeding SPARC-FEL with a fiber-based tunable ultraviolet source. The seed generation system consists of a kagomé hollow-core photonic crystal fiber filled with noble gas. Diffraction-limited DUV pulses of >50 nJ and fs-duration which are continuously tunable from below 200 nm to above 300 nm are generated. The process is based on soliton-effect self-compression of the pump pulse down to a few optical cycles, accompanied by the emission of a resonant dispersive wave in the DUV spectral region. The quality of the compression highly depends on the pump pulse duration, and ideally, pulses <60 fs should be used. Our experimental set-up and associated GENESIS simulations enable us to study the utility of the seed tunability, and the influence of the seed quality, on the performance of the SPARC-FEL in the 200-300 nm range.

THOC03

Measurement of the Transverse Coherence of the Sase FEL Radiation in The Optical Range Using an Heterodyne Speckle Method

551

M.D. Alaimo, M. Manfredda, M.A.C. Potenza, D. Redoglio
Universita' degli Studi di Milano & INFN, Milano, Italy
M. Artioli, F. Ciocci, L. Giannessi, A. Petralia, M. Quattromini, C. Ronsivalle, V. Surrenti, A. Torre
ENEA C.R. Frascati, Frascati (Roma), Italy
M. Bellaveglia, E. Chiadroni, G. Di Pirro, M. Ferrario, G. Gatti, A. Mostacci
INFN/LNF, Frascati (Roma), Italy
A. Cianchi
Università di Roma II Tor Vergata, Roma, Italy
V. Petrillo, L. Serafini
Istituto Nazionale di Fisica Nucleare, Milano, Italy
J.V. Rau
ISM-CNR, Rome, Italy

An heterodyne speckle approach has been applied for measuring the transverse coherence of FEL radiation in SASE regime in the optical region (400nm) at SPARC (LNF, Frascati - Italy). It turned out that the coherence length is comparable with the beam size and only slight variations of the coherence properties have been observed after the 5th undulator section. The technique needs a very essential setup composed only by a water suspension of commercial colloidal particles and a CCD camera. The Complex Coherence Factor is retrieved from the Fourier analysis of the interference pattern generated by the stochastic superposition of the almost spherical waves scattered by the particles and the unperturbed transmitted beam (heterodyne speckles). This approach does not require the engineering of ad-hoc devices and provides a two-dimensional map of the transverse coherence without any a-priori assumption about its functional form. The method is suitable for one-shot characterization and it works in the X-ray wavelength as well. It has been previously developed and tested to be effective with synchrotron radiation [*,**] (ID02 and ID06 at ESRF, Grenoble).
* M.D. Alaimo, M.A.C. Potenza, M. Manfredda, G. Geloni, M. Sztucki, T. Narayanan & M. Giglio, Phys. Rev. Lett. 10³ (2009).
** M. Manfredda et al., in preparation

Slides THOC03 [8.489 MB]

Paper	Title	Page
TUPD17	Seeding of SPARC-FEL with a Tunable Fibre-based Source	269
	N.Y. Joly University of Erlangen-Nuremberg, Erlangen-Nuremberg, Germany S. Bielawski PhLAM/CERCLA, Villeneuve d'Ascq Cedex, France W. Chang, P. Hölzer, K. Mak, P.St.J. Russell, F. Tani, J.C. Travers Max Planck Institute for the Science of Light, Erlangen, Germany F. Ciocci, L. Giannessi, A. Petralia, M. Quattromini ENEA C.R. Frascati, Frascati (Roma), Italy M.-E. Couprie, M. Labat, T. Tanikawa SOLEIL, Gif-sur-Yvette, France G. De Ninno, B. Mahieu Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy G. Gatti INFN/LNF, Frascati (Roma), Italy V. Petrillo Istituto Nazionale di Fisica Nucleare, Milano, Italy J.V. Rau ISM-CNR, Rome, Italy
	Instead of seeding a free electron laser in the UV-VUV with a frequency doubled or tripled laser or high order harmonics, here we investigate and present the first results on seeding SPARC-FEL with a fiber-based tunable ultraviolet source. The seed generation system consists of a kagomé hollow-core photonic crystal fiber filled with noble gas. Diffraction-limited DUV pulses of >50 nJ and fs-duration which are continuously tunable from below 200 nm to above 300 nm are generated. The process is based on soliton-effect self-compression of the pump pulse down to a few optical cycles, accompanied by the emission of a resonant dispersive wave in the DUV spectral region. The quality of the compression highly depends on the pump pulse duration, and ideally, pulses <60 fs should be used. Our experimental set-up and associated GENESIS simulations enable us to study the utility of the seed tunability, and the influence of the seed quality, on the performance of the SPARC-FEL in the 200-300 nm range.

THOC03	Measurement of the Transverse Coherence of the Sase FEL Radiation in The Optical Range Using an Heterodyne Speckle Method	551
	M.D. Alaimo, M. Manfredda, M.A.C. Potenza, D. Redoglio Universita' degli Studi di Milano & INFN, Milano, Italy M. Artioli, F. Ciocci, L. Giannessi, A. Petralia, M. Quattromini, C. Ronsivalle, V. Surrenti, A. Torre ENEA C.R. Frascati, Frascati (Roma), Italy M. Bellaveglia, E. Chiadroni, G. Di Pirro, M. Ferrario, G. Gatti, A. Mostacci INFN/LNF, Frascati (Roma), Italy A. Cianchi Università di Roma II Tor Vergata, Roma, Italy V. Petrillo, L. Serafini Istituto Nazionale di Fisica Nucleare, Milano, Italy J.V. Rau ISM-CNR, Rome, Italy
	An heterodyne speckle approach has been applied for measuring the transverse coherence of FEL radiation in SASE regime in the optical region (400nm) at SPARC (LNF, Frascati - Italy). It turned out that the coherence length is comparable with the beam size and only slight variations of the coherence properties have been observed after the 5th undulator section. The technique needs a very essential setup composed only by a water suspension of commercial colloidal particles and a CCD camera. The Complex Coherence Factor is retrieved from the Fourier analysis of the interference pattern generated by the stochastic superposition of the almost spherical waves scattered by the particles and the unperturbed transmitted beam (heterodyne speckles). This approach does not require the engineering of ad-hoc devices and provides a two-dimensional map of the transverse coherence without any a-priori assumption about its functional form. The method is suitable for one-shot characterization and it works in the X-ray wavelength as well. It has been previously developed and tested to be effective with synchrotron radiation [,] (ID02 and ID06 at ESRF, Grenoble). M.D. Alaimo, M.A.C. Potenza, M. Manfredda, G. Geloni, M. Sztucki, T. Narayanan & M. Giglio, Phys. Rev. Lett. 10³ (2009). ** M. Manfredda et al., in preparation
	Slides THOC03 [8.489 MB]