Temporal behavior of x-ray radiation emitted by subpicosecond KrF-laser-heated carbon preplasmas

Soft-x-ray emission dynamics in picosecond laser-produced plasmas

Plasmas were generated by prepulse-free picosecond laser irradiation of solid targets consisting of five different fluorine salts. Picosecond-time-resolved x-ray spectroscopy of K-shell emission from H-like and He-like fluorine was performed to study the temporal evolution of plasma parameters including electron density and temperature. Measurements show that the fluorine line emission intensity reaches its maximum in a time comparable with the rise time of the laser pulse. This peak is then followed by a decay whose rate depends upon the atomic number of the alkali component of the target. Our measurements show clear evidence of radiation cooling effects in higher-Z targets.

Picosecond soft-x-ray pulses from a high-intensity laser-plasma source

We report time-resolved spectroscopic analysis of laser-produced plasma x-ray sources. Plasmas produced by a 400-fs 1-TW tabletop laser are characterized with a transmission grating spectrometer coupled to a soft-x-ray streak camera. Soft-x-ray radiation in the 1-6-nm range with durations of 2-7 ps is observed for copper and tantalum plasmas. The effect of incident laser energy on the x-ray pulse duration is also investigated.