Experimental and theoretical study of longitudinally monomode vectorial solid-state lasers

The dynamics of a quasi-isotropic continuous-wave solid-state laser sustaining the oscillation of two orthogonally polarized eigenstates is experimentally investigated. A set of phase-sensitive vectorial Maxwell-Bloch equations is developed to describe theoretically the evolution of such a laser. Different temporal behaviors for the output intensities are observed, depending on the relative amounts and orientations of the phase and loss anisotropies and on the frequency of relaxation oscillations. Namely, the frequency locking of the two orthogonally linearly polarized eigenstates is shown to lead to a surprising pulsed mode-locked oscillation regime. In addition, for different values of the parameters, other peculiar operation regimes are found, such as cw circularly polarized, double-pulsed, or triple-pulsed output intensities. These experimental results, obtained using a diode-pumped Nd:YAG (YAG denotes yttrium aluminum garnet) laser, are well confirmed by the theoretical model.