The mandatory condition for efficient operation of an optically-pumped all-rare-gas laser (OPRGL) is the presence of rare gas metastable atoms in the discharge plasma with number density of the order of 10<sup>12</sup>-10<sup>13</sup> cm<sup>-3</sup>. This requirement mainly depends on the choice of a discharge system. In this study the number density values of argon metastable atoms were obtained in the condition of the dielectric-barrier discharge (DBD) at an atmospheric pressure.
This paper describes systematic measurements of pressure broadening coefficients for argon and krypton lines in an RF (radio-frequency) discharge plasma sustained in a mixture of inert gases. Using tunable diode laser spectroscopy we obtained experimental data for pressure broadening of argon and krypton lines. Pressure broadening coefficients were determined for Ar+Ne and Kr+Ne and Kr+Ar. For krypton, the isotopic structure of the line was taken into account and an appropriate fitting function was used to determine pressure broadening coefficients for the natural mixture of isotopes. These data may be used for diagnostics of the active medium of optically pumped all-rare-gas lasers.