Ne-like ion lasers in the extreme ultraviolet region

We report strong J=0–1, 3p-3s lasing in Ne-like scandium, calcium, potassium, and chlorine at wavelengths ranging from 35.3 nm in scandium to 52.9 nm in chlorine. The experiments were carried out with the ASTERIX IV iodine laser using a 15% prepulse 5.2 ns before the main pulse. These results extend the range of laser plasma x-ray lasers into the extreme ultraviolet region. Gain lengths between 7 and 11 were measured for the different lines. The 38.3-nm laser in calcium lased at an intensity as low as 5×${10}^{12}$ W/${\mathrm{cm}}^{\mathrm{-}2}$.