Prepulse technique for producing low-<i>Z</i>Ne-like x-ray lasers

We report an application of the prepulse technique which uses a low-intensity prepulse before the main optical drive pulse to prepare the plasma prior to lasing in low-Z, Ne-like ions. Ne-like x-ray lasers are now available over a previously inaccessible range of wavelengths. As an illustration of this technique we report an observation of lasing in ${\mathrm{Cr}}^{14+}$ and ${\mathrm{Fe}}^{16+}$ on the Ne-like J=0\ensuremath{\rightarrow}1, 3p\ensuremath{\rightarrow}3s transitions at 285 and 255 \AA{} as well as gain measurements for ${\mathrm{Ti}}^{12+}$.