Refractive Index Saturation Effects in Saturated Absorption Experiments

Saturation effects, occurring when a laser beam tuned close to a resonance propagates through an absorbing gaseous medium, were observed by means of a second beam sent in a nearly opposite direction. In addition to the well-known signal of saturated absorption, a signal directly related to the variation of the refractive index of the medium was observed. An experiment was performed to obtain simultaneously the signals of saturated absorption and saturated dispersion of iodine vapor.