Table-top extreme ultraviolet second harmonic generation

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 TiM2,3 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.

Automated summary

The lack of high flux and coherence in available table-top XUV sources has limited the use of nonlinear XUV and x-ray spectroscopies to free-electron lasers (FELs). This study demonstrates second harmonic generation (SHG) on a table-top XUV source, opening up new opportunities for studying element-specific dynamics.