Estimation of two-photon absorption characteristics by a global fitting procedure

A procedure for global fitting of open-aperture Z-scan data is proposed. It provides fast and reliable convergence, low sensitivity to the experimental noise, and the final results are not dependent on the quality of the initial approximations. The advantage of the global fitting is that it processes a set of experimental data measured by different incident intensities together, unlike conventional local fitting, which separately treats data at each intensity.