Observation of high transient gain in the germanium x-ray laser at 196 nm

Abstract

The transient-excitation pumping scheme, in which a picosecond duration pulse rapidly heats the plasma preformed by a low-intensity nanosecond pulse, was used to pump the Ne-like germanium, J=0–1 transition at 19.6 nm. A small-signal gain coefficient of 30 cm-1 was measured for targets ⩽5 mm long.