BEAM CHARACTERIZATION THROUGH ACTIVE MEDIA

The propagation laws for the width, angular spread and mean values of the intensity and of the radiant intensity of arbitrary beams as they pass through general active media are given. The relationship between the above parameters and the concept of beam quality is also pointed out. The thin-sheet bidimensional approach and the Wigner distribution function formalism are used. Analyses consider both, the homogeneously and inhomogeneously broadened cases, and the general conclusions include media with inhomogeneities in the refractive index, small-signal gain and saturation intensity. Comparison between propagation effects in passive and active media is outlined.