Resonantly photo-pumped Na-like X-ray lasers

Abstract

We examine the possibility of achieving X-ray lasing in Na-like ions by utilizing Ly-α or He-α radiation to resonantly photo-pump an electron from the n = 3 state of the Na-like ion to the n = 5 or 6 state with subsequent lasing between the n = 6→ n=5, n = 6 → n = 4, or n = 5 → n = 4 states of the Na-like ion. To identify potential resonances, we calculate all of the n = 3 → n = 5 and 6 transitions in Na-like ions which look favorable for pumping and identify the resonances which are possible with Ly-α or He-α radiation. Many promising laser candidates are identified, as well as an interesting near resonance, which runs across the periodic chart, between the He-α line and the 3 d→6 f Na-like transition.