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

Three-photon ionization of xenon, resonantly enhanced by the Xe 6p[12]0 state at 80 119 cm-1, is observed when a xenon atom simultaneously absorbs one ArF (51733-cm-1) and two XeF (28 482-cm-1) photons. For ArF and XeF laser intensities in the 1-100-MW cm-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[12]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 cm3s-1, respectively. Excitation of the 6p[12]0 state is both selective and intense and has resulted in lasing on the 6p[12]0→6s[32]1 transition at 828.0 nm, which represents the first optically pumped rare-gas laser.