Influence of the structure of a gain profile on the lasing dynamics of a solid-state ring laser

A mechanism is proposed for low-frequency self-modulation of the radiation emitted by a solid-state ring laser. This mechanism is based on the fine structure of the gain profile. A model of a laser with two closely spaced gain profiles is used to find the conditions of instability of unidirectional lasing. A numerical solution of a system of equations describing this situation confirms the correctness of the conclusions of this analysis and it shows that the processes described by the proposed model of a solid-state ring laser are indeed observed experimentally.