SATURATION EFFECTS IN 3-LEVEL SELECTIVE REFLECTION

We consider nonlinear selective reflection on the interface between di electric media and dilute vapors of three-level atoms. Assuming a pump -probe scheme with cascade-type excitation, we study the modification Delta R of the reflection coefficient of the probe induced by the pres ence of the pump. We extend previous calculations of the frequency spe ctrum of Delta R made for low probe power to the case of arbitrary pro be power. One then obtains a strong resonance which has already been o bserved experimentally. Moreover, for the two-photon resonance present in the low-intensity spectrum, a power splitting can be predicted wit h increasing intensity