Farey hierarchy in a bimode CO_{2} laser with a saturable absorber

Daniel Hennequin, Didier Dangoisse, Pierre Glorieux

Phys. Rev. A 42 6966 (1990)

We describe in this paper the dynamics of a bimode CO2 laser with an intracavity saturable absorber; more precisely the competition between the two modes when their single-mode regime is unstable and as simple as possible, i.e., with a single spike. The transition between the two modes occurs through a succession of periodic regimes separated by nonperiodic ones. The former are governed by the Farey arithmetic and lie on a staircase. Spectrum analyses and return maps suggest the existence of chaos in the nonperiodic states.