Tunable VUV and XUV light generation based on nonlinear resonantly enhanced four-wave mixing in gaseous media

The generation of coherent and narrow-band radiation sources in the short spectral regions of vacuum ultraviolet (VUV, λ = 100–200nm) and extreme ultraviolet (XUV, λ < 100nm) is a challenging endeavor that involves the third-order nonlinear susceptibility of the Mixing medium. In this paper, the experimental details and theory of the nonlinear process to generate tunable radiation in the VUV and XUV regions based on resonantly enhanced four-wave mixing in gaseous media are presented. The optimal experimental components and modes of operation of the setup will be shown and discussed. Moreover, the theory of four-wave mixing processes latitudes and limitations in gaseous media, i.e. phase matching conditions, gaseous medium refractive index rapid oscillatory behavior on resonance, quantum efficiency of the mixing process, mixing zone, and beam focusing will also be presented.