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In this study the optical properties of thin films made of deposited Ti or TiOx clusters produced in a laser vaporisation source are compared to those of films made by deposition of Ti atoms from an evaporator. TiOx films were fabricated by oxidising the films after titanium atom/cluster deposition, by growing the films in the presence of O2 or by adding O2 in the cluster source. The films were grown on transparent substrates such as quartz or CaF2. Using a grating spectrometer with a CCD-detector, optical extinction spectra in the UV and visible were recorded during deposition and, when applicable, during oxidation. When deposited at UHV conditions the Ti films show metallic characteristics, i.e. a rather uniform absorption in the whole spectral range, but during oxidation a bandgap emerges, seen as an increased transmission in the visible accompanied by an increasing extinction for shorter wavelengths. Even if the overall characteristics of the extinction spectra of the TiOx-films are similar, the peak structure in the UV depends on the method of oxidation. The in situ optical characterisation was supplemented with ex situ measurements in a spectrophotometer to obtain spectra of fully oxidised films, in which the bandgap was even more apparent. In order to analyse how different sample morphology influence the optical properties, the measured extinction spectra were compared to model spectra. Spectra were calculated using Mie theory for spherical particles, and using the quasistatic approximation for a oblate particles. The extinction by thin slabs was also calculated. |