Mechanism of the high-power RF-excited continuous atomic waveguide laser

Summary form only given. It was recently shown that the RF pumping of Xe-Ar-He gas at intermediate pressures leads to a dramatic rise of laser power in comparison with the well-known low-pressure DC excited Xe laser. The physical reasons of such a dramatic rise of laser parameters was not clear, however. Moreover, we observe specific space structures for the gain and output power of the RF-excited continuous Ar-He-Xe laser. The present contribution will treat this problem. We developed a model for the nonhomogeneous discharge of the active medium. From the solution of the Boltzmann equation, the production rates of the various species are obtained as a function of the position between the electrodes. In the electrode sheaths, there is a strong inhomogeneity of the plasma parameters. The relatively low electron concentration and high electric field near the electrodes create favorable conditions for the laser level inversion. The main source of the high-energy electrons is the diffusion from the bulk plasma. The secondary emission from the electrodes is almost negligible. Further, it will be shown that at high input powers, the refractive-index gradient due to gas heating leads to light space configurations, which are essentially different from the well-known modes of empty waveguides. The effective recombination mechanism of electrons with excimer ions in the regions with enhanced electric field near the walls together with the emission-field concentration provide favorable conditions for laser power production.