Nonlinear characterisation in the near infrared of PbS doped sol-gel thin films

Thin silica-titania planar waveguides doped with lead sulphide have been prepared on fused silica substrates using the sol-gel technique. The doping was realized by separate preparation of the matrix and the colloidal sol of the dopant, and successive mixing. Sulphide particles were obtained by reaction of metal acetates with thioacetamide and control of particle size was achieved by surface capping agents. PbS-doped films were densified for 1 h at 300°C in nitrogen. The particle size was estimated from XRD spectra using the Scherrer equation. Nonlinear measurement on several PbS-doped samples were carried out using the m-line technique.