Experiments on resonant photopumping of Mo VII for a VUV laser near 600 A

摘要

We present recent experimental data related to the resonant photopumping of Mo VII by Mo XII as a method of generating a VUV source near 600 angstroms. The experiment is based on a scheme proposed by Feldman and Reader in which the excitation of the 4p$+5$/6s $MIN 4p$+6$/ transition in Mo VII by the 5s $+2$/S$-1/2$/ $MIN 4p $+2$/P$-1/2$/ transition in Mo XII, produces a population inversion on one of several 6s - 5p transitions in Mo VII. The generation of plasmas suitable for photopumping experiments is established from the presentation of measurements of line emission from Mo plasmas as a function of laser and target parameters. Results of the laser produced plasma experiments show the successful enhancement of the population of the Mo VII 4p$+5$/6s upper lasing level when pumped by an adjacent Mo XII plasma. Additional results where the same Mo VII plasma was pumped by a Zr X plasma further support the conclusion of population enhancement by resonant excitation and not broadband photopumping effects. We also present results where improvements of the intensity of the Mo XII pump source, achieved using an additional pump laser, lead to the generation of a population inversion for a VUV transition.