The use of short laser pulses to generate high peak intensity, ultra-short x-ray pulses enables exciting new experimental capabilities, such as femtosecond pumpprobe experiments used to temporally resolve material structural dynamics on atomic time scales. PLEIADES (Picosecond Laser Electron InterAction for the Dynamic Evaluation of Structures) is a next generation Thomson scattering x-ray sour...

Recent experiments at KMS have been performed to investigate parameter variations of target component thickness, laser pulse duration and intensity, and one-sided vs two-sided irradiation in order to optimize the performance of the Livermore exploding foil selenium x-ray laser experiments. Preliminary experiments with selenium double foil targets were also conducted as a means of prolonging the...

At the new Free-electron LASer in Hamburg FLASH, we have studied photon-matter interaction by means of ion time-of-flight spectroscopy on gases in the soft X-ray regime. Emphasis was laid on the quantitative investigation of non-linear effects upon photoionization by the highly intense soft X-ray laser pulses. In the photon energy range from 38 to 93 eV, we have observed non-linearities due to ...

We have read with considerable interest the communication "Experimental Evidence of an X-Ray Laser" by J. G. Kepros, E. M. Eyring, and F. W. Cagle, Jr. (1). In our opinion the experimental observation of x-ray lasing has not been shown. Furthermore, under the conditions reported lasing at x-ray wavelengths is highly unlikely. In experiments where lasing is reported the single most important con...

Starting with the discovery of x-ray lasers in 1984, laser-created plasmas remained for almost a decade, the only medium in which large amplification of soft-x-ray radiation could be obtained. In this paper the recent first demonstration of large soft-x-ray amplification in a discharge-created plasma column, realized utilizing a fast capillary discharge to collisionally excite the 46.9 nm trans...

The temporal coherence of an injection-seeded transient 18.9 nm molybdenum soft x-ray laser was measured using a wavefront division interferometer and compared to model simulations. The seeded laser is found to have a coherence time similar to that of the unseeded amplifier, ~1 ps, but a significantly larger degree of temporal coherence. The measured coherence time for the unseeded amplifier is...

We investigated performance of ultrafast (30 fs –200 fs) laser-based x-ray source as an alternative to a microfocal x-ray tube used in micro-CT systems. A number of solid targets including Ge, Mo, Rh, Ag, Sn, Ba, La, Nd with matching filters was used. We optimized conditions for x-rays generation, measured x-ray spectra and obtained images of small animals using various characteristic x-ray lin...