He-Ne laser gain dependence on discharge current and gas pressure from resonant Faraday effect

Abstract

It is analyzed the influence of a longitudinal magnetic field on the operating mode of a He - Ne laser, knowing that the magnetic field is used for the suppressing of the λ 3.39 μm, which is amplificated in the same time with λ 632. 8 nm. It was used the Faraday magneto - optic effect at resonance, so that the λ 632.8 nm He-Ne laser radiation travels through a Ne - Ne mixture, with the pressures ratio p He /p Ne = 5, in population inversion conditions, placed in a longitudinal magnetic field. It was studied the laser medium amplification coefficient dependence on the parameters: discharge current intensity and total gas pressure. For the relation between the rotation angle of the polarization plane in a magnetic field and the laser amplification coefficient, in the He - Ne mixture, it was found a linear theoretical dependence. By fitting the experimental data, there are obtained nonlinear dependencies, for α(p) and α(I), which can be explained in the atomic collisions theory.