Attainment and investigation of vacuum ultraviolet parametric oscillation in an electric-discharge plasma

Vacuum ultraviolet radiation was generated in the range 124–126 nm by the method of four-wave mixing in a magnesium plasma produced in a pulsed electric discharge. This nonlinear medium was found to exhibit a high spatial homogeneity which made it possible to ensure phase matching. An experimental investigation was made of the characteristic features of parametric oscillation under conditions of two- and three-photon resonances in strong fields. It was found that the presence of an intermediate single-photon quasiresonance can lead to multifrequency vacuum ultraviolet oscillation. A conversion coefficient of ~ 10^– 3 was obtained for a pump input power of ~ 10 W.