Figure 6: Phase portraits for different laser wavelengths.

Phase portraits as a function of the free-carrier density (N) and the average temperature increase (ΔT) for λ_l below the supercritical Hopf bifurcation (a), at the bifurcation (b). Above the bifurcation we show the SP limit-cycle regime (c) and the situation in which the limit cycle is wiped out due to the interception with a second unstable fixed point (d). Solid (open) circles indicate stable (unstable) fixed points. The nullclines of equations (5) and (6) are plotted in green (=0) and blue (=0), respectively, while the simulated trajectories are in red. Grey arrows depict the temporal derivatives of ΔT and N in each point of the phase space, indicating the direction towards which the system would evolve.