Analysis of beam propagation in thick nonlinear media

We present a theoretical analysis of beam propagation in thick nonlinear media by using the Gaussian decomposition method and considering a thick medium as a stack of thin media. Simple analytic solutions of Z-scan characteristics and optical limiting with thick nonlinear media are obtained. Comparisons of these results with those obtained by use of a distributed-lens model and Gaussian-Laguerre mode decomposition are made. Good agreement is obtained with a distributed-lens model.