17-nm rubidium-ion laser

We demonstrate a rubidium-ion laser with two strong laser lines at 17.3 and 17.6 nm. The lasing transitions are 3p → 3s transitions in Ne-like rubidium. Gains of 1.9 and 1.4 cm−1 are measured for these two lines, respectively. This weak gain, as compared with that in other Ne-like laser systems, is ascribed to both the surface roughness of the target and the dilution associated with using rubidium chloride salt. In addition, three weaker lasing transitions are observed, including the anomalous J = 0 → 1 transition at 16.5 nm.