Influence of pressure on the Zeeman effect in a ring gas laser

A theoretical and experimental investigation is made of the influence of pressure on the interaction of the opposite waves in a Zeeman ring laser operated under single-mode conditions. It is shown that if radiation trapping is allowed for in the theory and the Doppler approximation is not used in calculations of the nonlinear polarizability of the active medium, the influence of pressure on the amplitude and frequency characteristics of a helium-neon laser utilizing the 2s₂–2p₄ transition at gas mixture pressures of up to 6–7 Torr may be described using a conventional phenomenological approach, in terms of a linear pressure dependence of the homogeneous line broadening and decay parameters of the upper and lower active levels.