<title>Kinetics of active media of He-Zn<formula><sup><roman>+</roman></sup></formula>, He-Cd<formula><sup><roman>+</roman></sup></formula>, He-Tl<formula><sup><roman>+</roman></sup></formula>, and Ne-In<formula><sup><roman>+</roman></sup></formula> hollow cathode lasers and new laser lines</title>

Abstract

The results of the theoretical and experimental study of the Zn⁺, Cd⁺, Tl⁺ and In⁺ ion levels population, gain and laser output power dependencies on the variation of hollow cathode discharge (HCD) parameters are presented. Pumping of excited metal ion levels goes through the thermal energy charge-transfer (CT) reaction between ground state buffer gas ions and neutral metal atoms, and second-kind collisions of HCD slow plasma electrons and atoms with excited metal ions, in redistributing the population amongst excited levels. A detailed kinetic model for negative glow plasma of HCD is based on affirmation that the total CT pumping rate for all metal levels is equal to buffer gas ionization rat and does not depend on CT cross section. Model uses the metal ion levels partial CT cross-section values which calculated based on Landau-Zener theory and Vigner spin rule and corrected accounting the experimental data, and uses the calculated transition probabilities in the Zn⁺, Cd⁺, Tl⁺ and In⁺ spectra in Coulomb approach taking into account the resonant trapping. The numerical calculations were made for the typical electron temperature (0,2...1eV) and density (0...10¹⁶ cm^-3), and other discharge parameters of the HCD laser plasma. The results of calculations for known laser transitions are in a good agreement with the experimental data and predict the laser action and laser parameters values at cw and pulsed regime of HCD for 7 new Zn⁺ laser transition (0,317...13,7 μm) in He-Tl mixture, for 15 new Cd⁺ laser transition (0,53...1,92 μm) in He-Cd mixture, for 45 new Tl⁺ laser transition (0,318...18,83μm) in He-Tl mixture and for 27 new In⁺ laser transition (0,294...11,08μm) in Ne-In mixture.