Abstract

Population density inversions in laser-produced plasmas between hydrogenic and helium-like carbon ion energy levels were obtained from measured resonance line comparisons^1,2. Such measurements have been extended to absolute flux from which the densities of potential lasing transitions are deduced. From this and the line width the gain coefficient can be derived. This becomes a vital gauge diagnostic in increasing the gain towards significant amplification by parameter variation for increased ion density and increased pumping. Calibration of the vacuum spectrograph for absolute intensity determinations is performed in the near-uv against a standard D₂ lamp and transferred to the 4 nm wavelength region by an in-situ branching ration technique involving resonance as well as high-lying transitions. Gains measured in electron-capture pumped plasmas are in agreement with a simple physical model from which parameter scaling is readily conceptualized. Expansion of the parameter space available for significant gain is predicted for higher-Z targets and for supplementary photon pumping.

© 1982 Optical Society of America