The instabilities and chaos in a CO2 laser containing SF6 and 15NH3 absorbers have been studied as a function of the parameters. By making use of a phase-portrait analysis, the instabilities have been classified through laser-control orbits in the phase space around the laser-with-saturable-absorber (LSA) fixed points. A chaotic regime, their a sequence of period-doubling bifurcations, has been observed for an instability of limit cycles reached through one fixed point. The transition between different instability operations presents an intermediate regime, around defined as the hesitation regime and have characterized through the fluctuations in the return times. which we have phenomena have been reproduced within a model, including the rotational–vibrational structure of The observed and absorber media. The numerical analysis has shown that the LSA time evolution, as described the amplifier orbits in the LSA phase space, depends on the relative attractions of the saddle point and the through homoclinic saddle focus fixed points.