Colloidal solutions of CdTe nanoparticles have been prepared by the "electropulse" technique. The diameters of the CdTe nanoparticles range from 5 to 30 nm. The goal of this work is to study the formation and evolution of the induced thermo-refractive index with a long-term goal of forming a thermal lens. An induced thermo-refractive index occurs when the CdTe solutions are irradiated with a strong laser beam. The experimental approach is derived from the Z-scan technique, a technique which is very sensitive to refractive index modulation in a sample. Thermo-optical coefficients, such as the thermal diffusivity, D, the characteristic build-up time of the thermal lens, t_c, and the induced thermo-refractive index can be determined from dynamic Z-scan curves. The thermo-optical coefficients have been determined at different wavelengths, beam powers, and for different nanoparticles sizes.

The third order nonlinear optical effect called the optical Kerr effect was studied in InP nanoparticles solutions. The synthesized InP nanoparticles have sizes ranging from 1.5 to 3.5 nm and each sample is characterized by its sizes distribution. The Z-scan technique was used to study nonlinear absorption and refraction. Different lasers were used, hence different nonlinear refraction effects were observed at different wavelengths (532, 633 and 1550 nm) and at different time scales (continuous and femtosecond).

A third-order non-linear optical effect, the optical Kerr effect, was studied in DR l-doped sol-gel using the Z-scan method which allows studying both processes of non-linear absorption and refraction. The materials under study are sol-gel substrates, amorphous silica glasses doped by the azo-dye Disperse Red 1. Modifying the conditions of the sol-gel synthesis, in particular the pH of the catalytic medium, enabled us to vary the morphology of the sol-gel substrate. Non-linear effects of various amplitudes were observed in sol-gel substrates of various porosities, involving different non-linear mechanisms.

We propose to extend the 'electropulse' technique to synthesize CdTe nanoparticles for optical components. To do so, we create nuclei of the expected material on a titanium electrode immersed in an electrolytic solution by using an electrochemical pulse. The nanoparticles are expelled from the titanium horn surface by cavitation bubbles, which are produced in the solution by a high intensity ultrasound pulse generated by a piezoelectric crystal. Optical absorption spectra and third-order non-linear optical properties of a colloidal solution of CdTe particles produced by this technique are presented. The non-linear refractive index was characterized using the single-beam z-scan technique, and measurements were carried out at several incidence intensities. Non-linear indices of refraction between -1.2×10^-7 and -2×10^-8 cm²W^-1 were measured.

Sol-gel derived silica glasses are well suited as host for molecular dopants that show specific optical properties, such as laser action (high second and third order nonlinear coefficients). Such materials are of interest in optical waveguide and switching for telecommunication networks. The material is prepared by sol-gel technique in which some nanocrystallites of semiconductor (II-VI) are included, specially CdTe. Nanocristallites are prepared out of the host matrix and included in the sol-gel after. The nanoparticles are prepared by sono-electrochemical technique. Sono-electrochemistry, or pulsed electrodeposition in presence of high intensity ultrasound, is used to produce powders. The nanoparticles are characterized by scanning and transmission microscopy, electron diffraction, and x-ray fluorescence. The nonlinear refractive index and absorption are measured by the Z-scan method at 532 nm (Nd-YAG pulsed laser).