Comparison of rate equation models for nonlinear absorption

Estimation of optical properties of the material depends not only on the experimental conditions, but also on the theoretical models used in the experimental data interpretation. This paper has focused on the rate Equations for two, three and four level models and solved the rate Equations analytically to interpret the effect of population dynamics in the nonlinear absorption process. In subsequent years we can see that researchers are using two rate Equation models to study the nonlinear absorption. In this article, the two models are comparatively studied under similar conditions and pictorially shown how these two models deviate from each other for same absorption cross-section and life-time parameters. The derived analytical solutions can be useful to the interested researchers in the lasers and nonlinear optics fields.