First EUV-induced TG

Four wave mixing induced by two EUV FEL pulses and probed with a fs ultraviolet pulse was demonstrated at the DiProI beamline.

Bencivenga et al., Nature 520, 205 (2015).

A miniaturized delay line composed of three 70 mm long carbon-coated mirrors, with position and pointing remotely controlled with piezo-motor actuators, fits within the DiProI end station. Each beam can be synchronized with the ultraviolet pump monitoring the FEL-induced ultrafast reflectivity change of a Si₃N₄ target. The time dependence of the transient grating signal is featured by a clear peak, centered at zero time delay and with a FWHM ≈ 150 fs, and modulations likely due to vibrations (Raman and Brillouin modes). An appreciable signal (> 10⁴ photons/shot) was observed in the whole probed time delay range (0-100 ps).

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Four-wave mixing experiments with extreme ultraviolet transient gratings.

F. Bencivenga, R. Cucini, F. Capotondi, A. Battistoni, R. Mincigrucci, E. Giangrisostomi, A. Gessini, M. Manfredda, I.P. Nikolov, E. Pedersoli, E. Principi, C. Svetina, P. Parisse, F. Casolari, M.B. Danailov, M. Kiskinova, C. Masciovecchio. Nature 520, 205 (2015).