%0 Journal Article %T Gain dynamics in a soft-X-ray laser amplifier perturbed by a strong injected X-ray field %+ NSF Center for EUV Science and Technology %+ Laboratoire d'optique appliquée (LOA) %+ School of Nuclear Science and Technology [Lanzhou] (SNST) %+ Laboratoire de physique des gaz et des plasmas (LPGP) %+ Oak Ridge National Laboratory [Oak Ridge] (ORNL) %+ Lawrence Livermore National Laboratory (LLNL) %A Wang, Y %A Wang, S. %A Li, L %A Oliva, Eduardo %A Berrill, M %A Yin, L. %A Nejdl, J. %A Luther, B.M. %A Proux, C. %A Le, T.T.T. %A Dunn, J. %A Ros, D. %A Zeitoun, Philippe %A Rocca, Jorge J. %< avec comité de lecture %@ 1749-4885 %J Nature Photonics %I Nature Publishing Group %V 8 %P 381–384 %8 2014-04-20 %D 2014 %R 10.1038/nphoton.2014.79 %Z Physics [physics]Journal articles %X Seeding soft-X-ray plasma amplifiers with high harmonics has been demonstrated to generate high-brightness soft-X-ray laser pulses with full spatial and temporal coherence. The interaction between the injected coherent field and the swept-gain medium has been modelled. However, no experiment has been conducted to probe the gain dynamics when perturbed by a strong external seed field. Here, we report the first X-ray pump–X-ray probe measurement of the nonlinear response of a plasma amplifier perturbed by a strong soft-X-ray ultra-short pulse. We injected a sequence of two time-delayed high-harmonic pulses (λ = 18.9 nm) into a collisionally excited nickel-like molybdenum plasma to measure with femtosecond resolution the gain depletion induced by the saturated amplification of the high-harmonic pump and its subsequent recovery. The measured fast gain recovery in 1.5–1.75 ps confirms the possibility to generate ultra-intense, fully phase-coherent soft-X-ray lasers by chirped pulse amplification in plasma amplifiers. %G English %L hal-01199046 %U https://ensta-paris.hal.science/hal-01199046 %~ X %~ ENSTA %~ CNRS %~ UNIV-PSUD %~ X-LOA %~ X-DEP %~ X-DEP-PHYS %~ ENSTA_LOA %~ UNIV-PARIS-SACLAY %~ UNIV-PSUD-SACLAY %~ UMR8578 %~ GS-PHYSIQUE