Parameters for Characterizing Broadband Gaussian Shell-Model Beams Propagating in Free Space

The beam propagation factor and kurtosis parameter of broadband Gaussian shell-model beams propagating in free space are studied numerically based on the intensity moments. The effects of spectral bandwidth and spatial correlation length on these two parameters are analyzed. The beam propagation factor or kurtosis parameter of beams with broader spectral bandwidth and smaller correlation length becomes larger. The parameters of broadband fully coherent Gaussian beams is less affected by the broad spectral bandwidth than those of broadband partially coherent Gaussian beams is.