WAVEGUIDE RAMAN SPECTROSCOPY AND OPTICAL STUDIES OF UNDOPED AND CdS-DOPED SOL-GEL DERIVED ZrO 2 THIN FILMS G. Ehrhart 1 , B.Capoen 2 , M.Bouazaoui 2 and S. Turrell 1* 1 Laboratoire de Spectrochimie Infrarouge et Raman (CNRS, UMR 8516); E-MAIL: sylvia.turrell@univ-lille1.fr and 2 Laboratoire de Physique des Lasers, Atomes et Molécules (CNRS, UMR 8523) ; Centre d’Etudes et de Recherches Lasers et Applications (CERLA), Université des Sciences et Technologies de Lille, F-59655 Villeneuve d’Ascq, France Keywords : sol-gel, thin films, semiconducting nanoparticles, Raman spectroscopy Abstract : This communication presents waveguide Raman spectra of ZrO 2 thin films. The evolution of structural and optical properties is studied as a function of increased annealing temperatures and doping with CdS nanoparticles. Zirconium and titanium oxide materials are of wide interest because of their excellent mechanical, thermal and optical properties. In particular, ZrO 2 with its low optical losses and very high linear refractive index is an excellent candidate for integrated devices for all-optical switching. Moreover, doping ZrO 2 with semiconductor nanoparticles such as CdS or PbS can confer an appreciable enhancement of the third order optical non-linearity, thus yielding glasses of interest for active components for telecommunications [1-2]. However, since optical properties are closely related to the microstructure, an understanding of the relation between the two is essential for every preparation technique. To date, very few publications have been devoted to structural studies of nanoparticle-doped ZrO 2 films. In the present work, polymeric solutions of ZrO 2 were synthesized by hydrolysis of zirconium n- propoxide in n-propanol, acetic acid, water and methanol. The resulting sols are colorless and stable for at least one month. This solution was filtered and dip-coated on pure silica substrates. Heat treatments under oxygen flow yielded homogeneous amorphous thin films. Five successive coatings provided crack-free two-mode waveguides which were used for optical loss measurements and waveguide Raman spectroscopic (WRS) studies. All optical measurements were performed using the prism coupling technique. M-lines spectra of the films (using λ= 633 nm) showed a gradual increase of the refractive index from 1.80 at 300°C to 1.93 at 500°C. The corresponding film thicknesses were observed to decrease from 100 to 80 nm. Finally, attenuation measurements demonstrated optical losses of less than 1 dB/cm. Figure 1 displays representative Stokes WRS spectra of undoped ZrO 2 waveguides for annealing temperatures varying from 300°C to 1000°C. At 300°C the vitreous structure is evidenced by the boson peak at 96 cm -1 and bands centered around 460 cm -1 and 550 cm -1 assigned to vibrations of matrix Zr-O-Zr groups and Zr-O ring structures, respectively. For temperatures up to 500°C, the shifts of these bands 500