Laser-driven soft-X-ray undulator source by Fuchs, M, Weingartner, R, Popp, A, Major, Z, Becker, S, Osterhoff, J, Cortrie, I, Zeitler, B, Hoerlein, R, Tsakiris, G, Schramm, U, Rowlands-Rees, T, Hooker, S, Habs, D, Krausz, F, Karsch, S, Gruener, F