NONLINEAR INTENSITY EFFECTS IN A LASER GENERATING THE 3 MAIN STANDING WAVES

The resonance condition is used to describe theoretically the three main kinds of standing waves with E-perpendicular-to-B (linear) and E-parallel-to-B (helicoidal and circular polarizations) that can be produced by the same laser and their nonlinear interaction with an atomic medium. It is shown that the saturation behavior of a single-mode gas laser is drastically modified by the nature of the operating standing wave. The predictions are checked experimentally with a laser from which each kind of standing wave can be generated with the same losses. The anisotropic structure of the saturation and in particular of the Lamb dip is isolated in each case. Very good agreement is observed between experiments and theory.