Berlin 2014 – scientific programme
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MO: Fachverband Molekülphysik
MO 23: Femtosecond Spectroscopy 3
MO 23.1: Talk
Friday, March 21, 2014, 14:00–14:15, BEBEL HS213
Transient grating spectroscopy with extreme ultraviolet light — E. F. Sistrunk1, J. Grilj1,2, J. Jeong3, M. Samant3, A. X. Gray4, H. A. Duerr4, M. Koch5, S. S. P. Parkin3, and •M. Guehr1 — 1PULSE, SLAC, Menlo Park, CA 94305, USA — 2EPFL Lausanne, CH-1015, Switzerland — 3IBM Almaden Research Center, San Jose, CA 95120, US — 4SIMES, SLAC, Menlo Park, CA 94305, USA — 5Experimental Physics, TU Graz, A-8010 Graz, Austria
Transient grating spectroscopy, introduced in the optical domain for its high signal-to-noise ratio at ultrafast time-resolution, has been a successful method for studying electronic and nuclear dynamics in molecules and solids. We demonstrate the first transient grating probed by ultrashort extreme ultraviolet pulses. The extreme ultraviolet range with photon energies from 10 to 100 eV provides element sensitivity on the important 3d transition elements via their 3p-3d core-to-valence resonances. We create a transient grating on VO2, which undergoes an insulator-to-metal transition (IMT) upon optical excitation with 800 nm pulses. The probe pulse is generated by strong field high harmonic generation (HHG) and contains photon energies at the vanadium 3p-3d transition. It probes the transient grating in a reflective geometry under grazing incidence. The first diffraction order of the transient grating shows spectrally resolved harmonics of the probe pulse. The diffraction intensity rises with a several picosecond time constant followed by a decay over >100 ps. In the talk we will discuss the different mechanisms of diffraction from the VO2 sample and the sensitivity to electronic and nuclear rearrangements in the IMT.