Nonlinear dynamics of a laser containing a modulated saturable absorber

In this paper, we report on the effect of an external force on the dynamical behavior of the ${\mathrm{CO}}_2$ laser with a saturable absorber. Different regimes have been obtained as the modulation amplitude or frequency is changed. These regimes are compared to the standard phenomenology of the circle map, i.e., the transition from quasiperiodicity to locked regimes and chaos according to the Farey hierarchy with Arnold tongues. Return maps of the trajectories reconstructed from time series are shown. These results are compared with those of numerical simulations based on a simple model of the laser with a saturable absorber.