Physical and optical characterization of thin films doped with Au Nanoparticles onto a silica substrate is presented. Films were prepared through sol-gel process, by using Au nanoparticles immersed in lipoic acid as dopant by means of hydrolysis and acid catalyzed reaction of tetraethyl-orthosilicate. The surface was characterized by SEM and AFM microscopies. Z-scan technique was used to measure nonlinear optical properties as nonlinear absorption and refraction indexes, using two different wavelengths. At 633 nm it was possible to observe nonlinear absorption only but at 514 nm both nonlinear properties were observed.
Characterization of thin films doped with organic metal materials onto a silica substrate is presented. Films were prepared through sol-gel process, by using macrocycles with Cu as dopant by means of hydrolysis and acid catalyzed reaction of tetraethylorthosilicate. Z-scan technique was used to measure nonlinear optical properties, nonlinear absorption and refraction indexes.
The optical characterization of nonlinear media through the Z-scan technique considers initially a thin
medium (with a thickness much less than the beam depth of focus). It has been observed that increasing the
thickness of the medium the transmittance increases, this means that n2 increases, for this reason we will
present a numerical model to determinate the minimum thin and the maximum thick medium limit. A thin
medium is considered as a thin lens with focal length F1 and a thick medium can be regarded as a set of such
thin lenses set with focal lengths F2, these lenses are contained in a medium whit a refraction index different
than air. This analysis is made through Matlab using the theory of Gaussian beams, ABCD matrices and the q
parameter, elementary theory in the development of this work, where the main feature of this model is that the
nonlinearity type of the medium is considered as an integer constant in its focal length3. We present the
graphs obtained from Z-scan for thick medium with both thermal and Kerr nonlinearities.