Experimental and theoretical study of monomode vectorial lasers passively Q switched by a Cr4+: yttrium aluminum garnet absorber

The dynamics of a solid-state laser sustaining the oscillation of two ortho gonally polarized eigenstates and passively Q switched by a Cr4+:YAG (YAG d enotes yttrium aluminum garnet) saturable absorber is experimentally invest igated. A set of rate equations in which the orientation-dependent interact ions between the intensities and the saturable absorber have been taken int o account is developed to describe theoretically the evolution of such a la ser. When a [001]-cut Cr4+:YAG plate is used, orthogonally polarized pulsed eigenstates are emitted either successively or simultaneously, depending o n the orientations of the eigenstates with respect to the crystallographic axes. Namely, in the latter case, beat note carrying pulses are emitted, wh ose beat frequency is continuously tunable. On the other hand, when a [111] -cut Cr4+:YAG plate is used, the simultaneity regime is never observed. All experimental results, obtained using a diode pumped Nd:YAG laser, are well confirmed by the theoretical model. [S1050-2947(99)02111-3].