Generation of ultrashort x-ray pulses

We report on the characterization of ultrashort (<10 psec at 1 keV), high-brightness (${10}^{20}$ photons/sec ${\mathrm{mm}}^2$eV into 2π sr at 1 keV) x-ray pulses. The pulses are generated by exciting a preformed laser-produced plasma using an ∼1 GW, picosecond laser pulse. Time-resolved measurements of the x-ray emission from a solid Au target are presented as well as the variation in the yield with laser energy and the angle of incidence. Time-integrated x-ray emission yields and spectra are presented for Si, Ti, and Au solid targets. Physical mechanisms responsible for the x-ray generation are discussed.