Soft x-ray pumping of metastable levels of Li+

Abstract

Soft x rays from a plasma generated by a neodymium: yttrium aluminum garnet laser beam (1.06 μm) are used to photoionize neutral Li vapor to produce Li+ metastables. Maximum metastable densities of Li+ (1s2s) 1S=6×1014 ions/cm3 and Li+ (1s2s) 3S=3×1015 ions/cm3 are obtained. The effective lifetimes of these levels are measured to be approximately 5 ns. At 50 mJ of incident laser energy the inferred conversion efficiency from 1.06-μm radiation to soft x rays is ∼14%.