Efficiency Characterization of Vacuum Ultraviolet Molecular Fluorine (F2) Laser (157 nm) Excited by an Intense Electric Discharge

A detailed experimental study of a discharge excited high pressure F2 laser is described. A theoretical kinetics model successfully described the characteristics of the F2 laser output. Although the F2 laser is operated in experiments at a less-fuel condition due to discharge instability at high F2 concentration, the upper laser level F2 (D)') is formed at a relatively high efficiency ~8%. The F2 laser efficiency is, however, significantly limited by the relatively long lifetime of the F2(A') lower laser level. Efficient energy extraction during the short effective gain time of the F2 laser needs a fast buildup of intracavity laser intensity by increasing a discharge current rise. Therefore, high pressure operation, where dissociation of F2(A') is accelerated and higher discharge pumping power is achieved, is very effective to increase both the F2 laser output and efficiency.