Electric-discharge He–N2 laser

An investigation was made of a helium-nitrogen pulsed electric-discharge laser emitting in two different bands of N₂⁺(B²Σ_u⁺–X²Σ_g⁺) and N₂(C³П_u–B³П_g). When the nitrogen content was of the order of a fraction of a percent, simultaneous lasing at 427.8 and 337.1 nm was observed and the output power was ~0.1MW at each wavelength. A theoretical model was used to derive analytic expressions describing the dependences of the energy of the radiation pulses on the concentrations of nitrogen and neon, and on the total pressure. Introduction of a small amount of neon demonstrated that the pumping of the upper active level N₂⁺(B) was via a charge transfer reaction, and not by direct electron impact. Collisional constants for the deactivation of the active levels were determined and it was found that deactivation of the N₂⁺(B) state in triple collisions with nitrogen molecules had a strong influence on the operation of the He–N₂ laser.