Abstract

A 140-mJ 100-ps duration 1.06-µm laser, focused with a cylindrical lens to a 1-cm line on a Ta target at an intensity of 6 × 10¹⁰ W/cm², produced sufficient XUV and soft-x-ray flux to obtain large inversions via inner-shell photoionization of Cd (Ref. 1) and Xe.² The short-wavelength emission from the Ta plasma is believed to result from a large number of transitions Ta VI predominantly in the 15–19-nm region. This is based primarily on spectral data in the 10–40-nm region produced by long-pulse (25-ns) irradiation of Ta (Ref. 3) and is confirmed by observation of strong Ta V recombination line emission in the 80–90-nm region in the current work. The Ta flux in the 15–19-nm spectral range is estimated to be of the order of 10²⁶ photons/s, which is sufficient to produce the large inversions observed in Cd and Xe.

© 1987 Optical Society of America