Nonlinear optical spectroscopies have significantly advanced the understanding of chemical dynamics at surfaces. One limitation in the optical regime has been the constrain to valence dynamics making probing in complex chemical environments and attributing dynamics to specific atomic species difficult. We now demonstrate second harmonic generation (SHG) on titanium in the extreme ultraviolet (XUV) using a femtosecond table-top laser. We show that the observed XUV-SHG emission is specific to the inversion-symmetry broken surface of titanium. These findings open new possibilities to study chemical dynamics at surfaces and buried interfaces from the viewport of a specific atomic species.

In collaboration with Institut Polytechnique de Paris, UC San Diego, SLAC National Accelerator Laboratory, and the Friedrich Schiller University Jena.

Congratulations to Emma for her first shared-first author paper and to Lars for his first paper in the group!

Our paper appeared in Science Advances and was selected as cover featured article:
https://advances.sciencemag.org/content/7/21/eabe2265
Press release from the College of Chemistry:
https://chemistry.berkeley.edu/news/berkeley-researchers-demonstrate-new-technique-surface-sensitive-second-harmonic-generation