Abstract

The Z-scan technique [1] is an extensively utilized experimental technique for studying optical nonlinearities in a wide class of photorefractive media. The results of interpretation of Z-scans lead, at least sometimes, to conclusions of non-acceptably large uncertainties in estimation of the Δn₀ and n₂ indices. This vagueness is observed, for example, in nonlinear materials exhibiting strong absorption saturation, which can considerably distort the ordinary Z-scan transmittance curves owing to deviations of the radial refractive index profile Δn(r) from the Gaussian one. Consequently, simple formulas [1] do not work in such circumstances; otherwise, significant discrepancy between the actual and the calculated values for Δn₀ arises.

© 2000 IEEE