TRAICHE, M.2019-06-062019-06-062018-02-05https://dspace.univ-eloued.dz/handle/123456789/2444Séminaire National Sur Laser Solaire Et Matériaux ElOeued 5-6 Février 2018I treat the Z-scan technique applied to characterize a non linear material, probed by a laser beam on one of its atomic transitions. By assuming the caustic of the probing optical beam in accordance with the geometric optics approximation, I model the Z-scan setup. I describe a Zscan experiment I performed in CDTA on a ruby crystal sample with a top hat laser beam from a Nd:YAG laser followed by a second harmonic generator. The experimental and theoretical Z-scan curves, thus obtained, show good agreement. The cubic non linearity in the material sample, ruby, is eventually determined.enZ-scan Technique; theoretical modeling; Z-scan experiment, Non linear optical material.Other