Stimulated emission of argon dimers excited by a pulsed plasma-cathode discharge

Results are reported from a theoretical and experimental investigation aimed at obtaining lasing on transitions of an Ar-2 excimer laser pumped by a pulsed electric discharge. It is shown that by using a recently developed plasma-cathode discharge, quasi-cw excitation of the laser active medium can be achieved with a gain of around 0.1 cm(-1). The results of preliminary experiments performed using a model system indicate an effect wherein the duration of the spontaneous emission at the lambda=126 nm transition of the Ar-2 dimer decreases monotonically as its peak intensity increases. This behavior, which is observed with increasing pump intensity, is evidence of a stimulated emission effect in the system. However, the measurements indicate that no amplification takes place in the active medium because of accidental impurities in the working gas. (C) 1997 American Institute of Physics. [S1063-7842(97)00911-2].