MODELS, PREDICTIONS, AND EXPERIMENTAL MEASUREMENTS OF FAR-INFRARED NH3-LASER DYNAMICS AND COMPARISONS WITH THE LORENZ-HAKEN MODEL

Dynamics of the intensity and optical field amplitude of a coherently pumped far-infrared NH3-laser are measured and characterized. The expe rimental findings in certain parameter ranges closely follow the dynam ics of the Lorenz model and its generalization for laser systems. Simi larities and some specific differences are found in geometrical or sta tistical characterizations of the attractors. The experimental results are also consistent with the results of a model of optically pumped t hree-level lasers which takes into account the presence of a multiplic ity of velocity groups as well as three-level coherence effects. For a certain region in parameter space, this far more complex model with a much larger phase space produces results similar to the dynamics of t he Lorenz model. The model also provides explanations of differences b etween the experimental results and results from the Lorenz model.