Soft-X-ray lasers with charge transfer pumping in a mixture of clusters and atomic gases

Charge transfer in low-energy collisions of bare nuclei with atoms or parti ally stripped ions is a promising pumping mechanism for soft-x-ray lasers. For the demonstration of soft-X-ray lasers with charge transfer pumping, th e use a mixture of clusters and atomic gases is suggested. When an intense femtosecond laser pulse is focused into such a medium, the clusters will be ionized to much higher ionization stages than the atoms. This allows creat ion of very favourable conditions for efficient charge transfer pumping.