Complex intermittent dynamics in large-aspect-ratio homogeneously broadened single-mode lasers

Spatio-temporal dynamics of a homogeneously broadened single-mode laser with large Fresnel number is investigated above the second laser threshold. The system is described by the two-level Maxwell-Bloch equations. A simple quasi-periodic regime is observed when the cavity is tuned below resonance, and very uncommon dynamics is obtained when the cavity is tuned above resonance. In the latter case, the laser intensity presents “plateaux” of nearly constant values which are interrupted by bursts of large amplitude oscillations. The underlying dynamics is described in terms of heteroclinic connections between unstable periodic orbits associated with constant intensities. A very surprising characteristic of this dynamics is that the periodic orbits are always visited in a given order which is related to the sequence of wave vectors selected by the laser. This new type of behavior presents many characteristics of intermittency.