Four wave mixing using coherent FEL radiation

The development of Free Electron Laser sources is opening up the possibility to probe dynamics at the femtosecond-nanometer time-length scales. A remarkable step forward towards this goal would be achieved by extending the Four Wave Mixing (FWM) approach at VUV/soft x-ray wavelengths. FWM-based techniques allow a coherent control in both the stimulating and probing processes of photon-induced excitations. We propose to exploit the FERMI@Elettra seeded Free Electron Laser (FEL) source to put on practice the VUV/soft x-ray FWM approach, yet theoretically conceived one decade ago. Moreover, the exploitation of VUV/soft x-ray wavelengths allows adding site-sensitivity to FWM methods by exploiting core resonances of selected elements in the sample.