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

Abstract

Three-photon ionization of xenon, resonantly enhanced by the $\mathrm{Xe}6p{\left[\frac{1}{2}\right]}_0$ state at 80 119 ${\mathrm{cm}}^{-1\mathrm{}}$, is observed when a xenon atom simultaneously absorbs one ArF (51733-${\mathrm{cm}}^{-1\mathrm{}}$) and two XeF (28 482-${\mathrm{cm}}^{-1\mathrm{}}$) photons. For ArF and XeF laser intensities in the 1-100-MW ${\mathrm{cm}}^{-2\mathrm{}}$ 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 $6p{\left[\frac{1}{2}\right]}_0$ level and the rate constant for quenching of the state by background Xe atoms were measured to be 29±4 ns and 4±1 × ${10}^{-10\mathrm{}}$ ${\mathrm{cm}}^3$ ${\mathrm{s}}^{-1\mathrm{}}$, respectively. Excitation of the $6p{\left[\frac{1}{2}\right]}_0$ state is both selective and intense and has resulted in lasing on the $6p{\left[\frac{1}{2}\right]}_0\to 6s{\left[\frac{3}{2}\right]}_1$ transition at 828.0 nm, which represents the first optically pumped rare-gas laser.