%0 Generic %A Darvasi, Gabor %D 2011 %F heidok:13204 %R 10.11588/heidok.00013204 %T Optische Kontrolle der Lasertätigkeit im Röntgenbereich %U https://archiv.ub.uni-heidelberg.de/volltextserver/13204/ %X X-ray free-electron lasers have revolutionized x-ray science by achieving unprecedented intensities exceeding 10^18 W/cm^2. However, they lack temporal coherence and controllability of their pulses' temporal and spatial properties, which is essential for many applications. We investigate the possibility to control and shape x-ray laser pulses with optical light. An optical laser pulse is used to control the population inversion on the 2p-1s transition in a neon x-ray laser pumped by an x-ray free-electron laser. Theoretical results are presented based on population and photon rate equations. We study the dependance of the x-ray laser's output on the pump pulse's and the optical laser pulse's properties. Small-signal gain calculations reveal that for a high degree of control narrowband pumping radiation is required and the optical laser pulse must have precise timing with respect to the pump pulse. Self-consistent gain calculations show that it will be possible to do spatial pulse shaping and to produce high-intensity, sub-femtosecond pulses that are controlled by and synchronized to the optical laser pulse with femtosecond precision. Our results indicate that the presented scheme would make it possible to establish pump-probe techniques with femtosecond x-ray and optical pulses.