Electric-discharge He–N2laser

Abstract

An investigation was made of a helium-nitrogen pulsed electric-discharge laser emitting in two different bands of N2+(B2Σu+–X2Σg+) and N2(C3Πu–B3Πg). 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.