- Helk, Tobias;
- Berger, Emma;
- Jamnuch, Sasawat;
- Hoffmann, Lars;
- Kabacinski, Adeline;
- Gautier, Julien;
- Tissandier, Fabien;
- Goddet, Jean-Philipe;
- Chang, Hung-Tzu;
- Oh, Juwon;
- Pemmaraju, C Das;
- Pascal, Tod A;
- Sebban, Stephane;
- Spielmann, Christian;
- Zuerch, Michael
The lack of available table-top extreme ultraviolet (XUV) sources with high enough fluxes and coherence properties has limited the availability of nonlinear XUV and x-ray spectroscopies to free-electron lasers (FELs). Here, we demonstrate second harmonic generation (SHG) on a table-top XUV source by observing SHG near the Ti M2,3 edge with a high-harmonic seeded soft x-ray laser. Furthermore, this experiment represents the first SHG experiment in the XUV. First-principles electronic structure calculations suggest the surface specificity and separate the observed signal into its resonant and nonresonant contributions. The realization of XUV-SHG on a table-top source opens up more accessible opportunities for the study of element-specific dynamics in multicomponent systems where surface, interfacial, and bulk-phase asymmetries play a driving role.