Third Order Optical Nonlinearities of C 450 Doped Polymer Thin Film Investigated by the Z-Scan

Abstract

In the present work, z-scan technique was used to study the nonlinear properties, repr esented by nonlinear refractive index and nonlinear absorption coefficient for Coumarin 450 (C450 ) doped PMMA as a function of concentration for two different solvents. The results show change of the effect from self-focusing to self-defocusing in closed aperture z- scan (or change of the effect from two photon absorption to saturable absorption in open aperture z-scan), when the sample dissolved in low viscosity and more polar solvent