Nonlinear processes in the extreme ultraviolet region using the FEL FERMI@elettra

The advent of Free Electron Lasers (FELs) operating in the extreme ultraviolet (XUV) and X-ray spectral range [1] provides access to the investigation of the nonlinear interaction of atoms, molecules, and clusters under intense fields in this region of the electromagnetic spectrum.

I will review recent experimental results obtained at the FEL FERMI@Elettra, which, thanks to the seeding scheme, offers unprecedented characteristics in terms of photon tunability, pulse-to-pulse energy stability, and coherence properties [2]. These properties allow the investigation of nonlinear resonant photoionization processes [3] and the extension of coherent control schemes to the XUV spectral range [4,5].

References
[1] B. W. J. McNeil and N. R. Thompson "X-ray free-electron lasers" Nature Photonics 4, 814–821 (2010)
[2] E. Allaria et al. "Highly coherent and stable pulses from the FERMI seeded free-electron laser in the extreme ultraviolet" Nature Photonics 6, 699 (2012).
[3] A. Grum-Grizhmailo et al. "Interfering one-photon and two-photon ionization by femtosecond VUV pulses in the region of an intermediate resonance" Phys. Rev. A 91, 063418 (2015)
[4] A. Dubrouil et al. "Two-photon resonant excitation of interatomic coulombic decay in neon dimers" J. Phys. B: At. Mol. Opt. Phys. 48 204005 (2015)
[5] K. C. Prince et al. "Coherent control with a short-wavelength Free Electron Laser" submitted