We carried out Z-scan measurements on lyotropic liquid crystals and on lyotropic liquid crystals doped with ferrofluid. In these experiments, the sample is translated through the focal region of a focused Gaussian laser beam. The dependence of the far-field intensity on sample position due to intensity-dependent optical nonlinearities has been analyzed on the basis of the thermal-lens model of Gordon et al. and the Gaussian decomposition analysis of Sheik-Bahae et al. The thermal-lens model is nonlocal in space and time, whereas the Gaussian decomposition is predicated on a strictly local response. We compare the goodness of fit of the predictions of these models to experimental data, and we discuss limitations of these models in describing Z-scan experiments on systems with nonlocal response.
© 2002 Optical Society of America
Fabio Luiz Sant’Anna Cuppo, Antônio Martins Figueiredo Neto, Sergio Leonardo Gómez, and Peter Palffy-Muhoray, "Thermal-lens model compared with the Sheik-Bahae formalism in interpreting Z-scan experiments on lyotropic liquid crystals," J. Opt. Soc. Am. B 19, 1342-1348 (2002)