Speaker
Dr
Laura Foglia
(Elettra Sincrotrone Trieste)
Description
The advent of free-electron-laser (FEL) sources provided pulses of extreme ultraviolet (EUV) and soft to hard X-ray radiation with coherence and time-duration comparable to those of table-top fs-laser sources.
In the first place, this led to the extension from the optical to the short-wavelength regime of time-domain techniques, allowing the direct measurement of decay times of fundamental excitations in matter. Now, after one decade of operation, FELs have allowed the development of experiments at the crossroad between typical table-top laser and synchrotron techniques, the evolution of X-ray non-linear optics and the emergence of new experimental approaches. The FERMI facility in Trieste (Italy) is unique in the FELs landscape because of its seeded emission scheme, resulting in superior performances in terms of shot-to-shot pulse stability. Of particular interest for spectroscopic applications are its broad tunability, spectral purity (approaching the Fourier-transform limit), sub-linewidth stability and timing jitter. Transverse and temporal coherence are those expected from a true laser, and have been exploited in a series of pioneering experiments both in non-linear optics and in atomic and molecular physics.
In this talk, I will present an experimental scheme for two-dimensional X-ray absorption spectroscopy, which uses FERMI in the optical klystron configuration, thus simulating the stochastic emission of SASE sources. Then, I will show how non-linear optical schemes, and in particular transient grating spectroscopy can be exploited for single shot determination of spectral and temporal characteristics of FEL pulses. Finally, I’ll discuss a novel approach to extend transient grating spectroscopy to the hard X-ray regime, where, up to now, attempts were hampered by shot-to-shot pulse fluctuations.
Primary author
Dr
Laura Foglia
(Elettra Sincrotrone Trieste)
Co-authors
Dr
Cristian Svetina
(PSI)
Ms
Emanuele Pedersoli
(Elettra Sincrotrone Trieste)
Dr
Emiliano Principi
(Elettra Sincrotrone Trieste)
Filippo Bencivenga
(Elettra-Sincrotrone Trieste)
Dr
Flavio Capotondi
(Elettra Sincrotrone Trieste)
Dr
Pamela Bowlan
(Los Alamos National Lab)
Dr
Riccardo Mincigrucci
(Elettra Sincrotrone Trieste)
Dr
William Peters
(Los Alamos National Lab)
