Efficient route to saturation in collisionally pumped, soft-x-ray lasers

Abstract

Many laboratories have demonstrated significant amplification on the 2${\mathit{p}}^{5}$3p\ensuremath{\rightarrow}2${\mathit{p}}^{5}$3s J=0\ensuremath{\rightarrow}1 transition of Ne-like ions. The slow Z scaling of the energy of this transition suggests an efficient means of demonstrating saturation at xuv wavelengths. We present a detailed analysis of lasing in Ne-like Fe slab targets, especially considering the 255 \AA{} J=0\ensuremath{\rightarrow}1 transition, which is calculated to totally dominate the output. The calculations indicate that it is possible to saturate this line with driving energies \ensuremath{\sim}30 J, even allowing for the known tendency of calculations to overestimate the gain on this line. Such driving requirements represent more than an order of magnitude increase in efficiency from what has so far been accomplished using similar systems of comparable wavelength. Small-scale facilities with high repetition rates are capable of providing the necessary driving conditions.