41.8-nm Xe8+ laser driven in a plasma waveguide

An experimental demonstration of an optical field ionization short-wavelength laser driven in a gas-filled capillary-discharge waveguide is described in detail. Guiding of high-intensity laser pulses has previously been demonstrated with this type of waveguide for capillary discharges in hydrogen. For the present experiments xenon gas was mixed with the hydrogen, and strong lasing on the 4d95d-4d95p transition in Xe8+ at 41.8 nm was observed. Under optimum conditions the short-wavelength laser output achieved with the waveguide was found to be greater than that from a Xe gas cell. Measurements of the transmission of the pump laser pulses through the waveguide show that the short-wavelength laser signal was greatest under conditions for which the pump laser pulses were well guided. Simulations of the propagation of the pump laser radiation are presented for a range of initial plasma conditions, and these indicate that the laser-plasma interaction length achieved was greatly increased compared to that which can be achieved in a gas cell