Measuring Nonlinear Refraction And Its Dispersion

We describe methods for measuring the nonlinear refraction of nominally transparent materials that involve propagation from the near to the far field, which changes a phase distortion into an amplitude redistribution. These methods include beam distortion methods and Z-scan. We also look at methods to determine the spectral dependence of these changes in refractive index. Recent advances here include using femtosecond white-light continua as the source for Z-scan. The types of nonlinear refractive mechanisms are also briefly discussed including bound-electronic, excited state or free-carrier generation, reorientation, electrostrictive, and thermal nonlinear refraction as well as cascaded second-order nonlinearities. © 2009 Springer New York