Citation:
B. Bergues, Rivas, D. E, Weidman, M. , Muschet, A. A, Helml, W. , Guggenmos, A. , Pervak, V. , Kleineberg, U. , Marcus, G. , Kienberger, R. , Charalambidis, D. , Tzallas, P. , Schröder, H. , Krausz, F. , and Veisz, L.. 2018.
“Tabletop Nonlinear Optics In The 100-Ev Spectral Region”. Optica, 5, Pp. 237–242. doi:10.1364/OPTICA.5.000237.
Abstract:
Nonlinear light&\#x2013;matter interactions in the extreme ultraviolet (XUV) are a prerequisite to perform XUV-pump/XUV-probe spectroscopy of core electrons. Such interactions are now routinely investigated at free-electron laser (FEL) facilities. Yet, electron dynamics are often too fast to be captured with the femtosecond resolution of state-of-the-art FELs. Attosecond pulses from laser-driven XUV-sources offer the necessary temporal resolution. However, intense attosecond pulses supporting nonlinear processes have only been available for photon energy below 50&\#x00A0;eV, precluding XUV-pump/XUV-probe investigation of typical inner-shell processes. Here, we surpass this limitation by demonstrating two-photon absorption from inner electronic shells of xenon at photon energies around 93&\#x00A0;eV and 115&\#x00A0;eV. This advance opens the door for attosecond real-time observation of nonlinear electron dynamics deep inside atoms.
