Nonlinear-optical processes in the near-resonant two-photon excitation of xenon by femtosecond KrF-excimer-laser pulses

The nonlinear response of xenon gas due to a near-resonant two-photon excitation at the 5${\mathit{p}}^6$ ${}_{}{}^1{}_{}{}^{}$ ${\mathit{S}}_0$→6p[1/2${]}_0$ transition with a femtosecond KrF-excimer-laser system is investigated for the intensity range ${10}^{10}$–${10}^{15}$ W/${\mathrm{cm}}^2$. Stimulated hyper-Raman scattering and amplified spontaneous emission of atomic xenon are observed at wavelengths around 823 and 828 nm. These emissions are superimposed by four-wave parametric-oscillation processes leading to strong ultrashort continuum radiation in the visible and near-infrared (650–850 nm), uv (185–400 nm), and vacuum ultraviolet (147–155 nm) spectral ranges with output powers up to 100 MW. From difference-frequency-mixing experiments microscopic nonlinear susceptibilities in the range of ‖${\mathrm{\chi }}^{\mathrm{}\left(3\right)\mathrm{}}$‖=${10}^{\mathrm{-}48}$ to ${10}^{\mathrm{-}50}$ ${\mathrm{m}}^5$/${\mathrm{V}}^2$ have been determined, which are in good agreement with calculations.