The development and the construction of X-ray free electron lasers (XFELs) has allowed the implementation of an entirely novel class of experiments. Among these, non-linear X-ray studies are becoming possible thanks to the high flux and extremely short durations of X-ray pulses from XFELs. Methods such as four-wave mixing, transient gratings, stimulated Raman, multiphoton absorption, etc. have recently been demonstrated.
It is in this context that the WavemiX (Wave mixing in the X-ray) network was created. Its goal is to bring together the community of scientists working on the development of novel non-linear X-ray optical and spectroscopic methods and experiments, as they share common theoretical and technical challenges. This synergy and sharing of expertise and know-how is of high importance in order to foster the implementation of new tools based on the above methods.