Study of population relaxation and of collisional excitation transfer in an He–Ne laser by the nonlinear modulation spectroscopy method

An amplitude version of the nonlinear resonant modulation spectroscopy method was used to demonstrate that a strong redistribution of the channels and probabilities of collisional excitation transfer within the neon 2p multiplet, compared with those in pure neon, occurred in the discharge tube of an He–Ne laser. The following values were found for the coefficient of transfer to the 2p₄ level: γ₂₄ = 0.12, γ₃₄ = 0.02, γ₅₄ = 0.33. The minimum values of the detectable gain (loss) were 10 MW^–1 and 0.6 MW^–1 respectively for the cw and pulsed laser systems.