Femtosecond measurement of nonlinear absorption and refraction in CdS, ZnSe, and ZnS

Abstract
The nonlinear index of refraction and the two‐photon absorption coefficient of CdS, ZnSe, and ZnS were measured using the Z‐scan technique with 100‐femtosecond pulses at 610 nm, 780 nm, and 1.27 μm. The results are in reasonable agreement with measurements made at similar wavelengths with longer pulses. A simple theoretical model accounts for the dispersion of the nonlinearities and confirms their electronic nature.