Effect of a resonant medium on the polarization of a light pulse

The propagation of a 2π pulse in an ensemble of paramagnetic ions in a magnetic field is analyzed. The paramagnetic part of the magnetooptic activity of the medium contributes to the rotation of the polarization of the light pulse. The Faraday-rotation angle for a 2π pulse which has passed through the medium can be controlled by varying the saturation of the magnetic resonance.