In this work, we report the fabrication of silver (Ag) nanoparticles on silica substrate in vacuum by PLD using a
third harmonic of Nd:YAG laser (λ = 355 nm). The existence of Ag nanoparticles was evidenced by transmission
electron microscopy (TEM) and an analysis of the size of the nanoparticles as a function of the number of laser pulses
was performed. The Ag nanoparticles produced had mean diameters in the range from 1 nm to 15 nm, with the size
distribution centered near 5 nm. The presence of the Ag nanoparticles was also evidenced from the appearance of a
strong optical absorption band into the measured UV-VIS spectra, associated with surface plasmon resonance.
Broadening of the absorption peak and its shifting to the longer wavelengths was observed as the number of laser pulses
increased. A theoretical study of the optical properties of Ag nanoparticles predicts the presence of a thin oxide shell
covering the nanoparticles.
We report on the results of ultraviolet (UV)-assisted annealing of thin Y2O3 films produced by pulsed laser deposition. An excimer XeCl laser was used for ablation of Y2O3 ceramic target. The films were grown on (001) SiO2 substrates at 500 °C and oxygen pressure of 0.05 mbar. The effect of UV-assisted laser annealing on the structure, morphology, and optical properties was investigated. The UV-assisted annealing was performed by the same laser. The beam was directed parallel or toward the surface of the as-deposited films. The influence of the ambient gas (O2 or N2O) is explored. The ambient atmosphere has an influence on the preferential (cubic or monoclinic) phase of gowth while it has no significant effect on the surface morphology. The absorption coefficient in the VIS range has a lower value for the films annealed with laser directed parallel to the surface independently on the gas environment. Annealing of the films with laser beam directed at the film surface slightly increases the refractive index, independently of the gas ambient.
Thin TiO2 films were grown on (001) SiO2 substrates using excimer KrF laser ablation of ceramic targets. The influence of deposition temperatures at fixed oxygen pressure of 10 Pa on the crystal and optical properties of the films was investigated. Structural characterisation by X-ray diffraction and Raman spectroscopy shows preferential crystallization of the anatase TiO2 films were obtained at high temperatures of 500 and 600 °C, respectively. Optical transmission as high as 92% in the visible spectral region was measured for films grown at temperatures higher than 400 °C. The refractive index and the thickness of the films measured by m-line spectroscopy shows the highest values of 2/41 and 250 nm, respectively, at deposition temperature of 600 °C.