ULTRASHORT X-RAY PULSES

In this paper, we discuss recent advances in ultrashort-pulse X-ray te chnology. Femtosecond laser-plasma based X-ray sources can now generat e sub-picosecond soft X-ray pulses, with photon energies from almost-e qual-to 10 eV to almost-equal-to 10(6) eV, and with a high conversion efficiency of incident laser light to broadband X-rays. Recent advance s in high-speed X-ray detectors and soft X-ray optics make it practica l to use such sources as experimental tools for time-resolved X-ray sc ience. Other possible generation techniques, such as laser-electron-be am scattering, promise to further expand the experimental capabilities in this area.