Resonantly enhanced, three-photon ionization of Xe: Optically pumped rare-gas laser

Abstract

Three-photon ionization of xenon, resonantly enhanced by the $\mathrm{Xe}6p{[\frac{1}{2}]}_{0}$ state at 80 119 ${\mathrm{cm}}^{\ensuremath{-}1}$, is observed when a xenon atom simultaneously absorbs one ArF (51733-${\mathrm{cm}}^{\ensuremath{-}1}$) and two XeF (28 482-${\mathrm{cm}}^{\ensuremath{-}1}$) photons. For ArF and XeF laser intensities in the 1-100-MW ${\mathrm{cm}}^{\ensuremath{-}2}$ range, the peak electron density is more than an order-of-magnitude larger than that obtainable by the nonresonant, two-photon ionization of Xe by ArF. The spontaneous radiative lifetime of the $6p{[\frac{1}{2}]}_{0}$ level and the rate constant for quenching of the state by background Xe atoms were measured to be 29\ifmmode\pm\else\textpm\fi{}4 ns and 4\ifmmode\pm\else\textpm\fi{}1 \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}10}$ ${\mathrm{cm}}^{3}$${\mathrm{s}}^{\ensuremath{-}1}$, respectively. Excitation of the $6p{[\frac{1}{2}]}_{0}$ state is both selective and intense and has resulted in lasing on the $6p{[\frac{1}{2}]}_{0}\ensuremath{\rightarrow}6s{[\frac{3}{2}]}_{1}$ transition at 828.0 nm, which represents the first optically pumped rare-gas laser.