The characterisation of TiO2 as a single layer and as an 8-layer dielectric stack was successfully carried out with the UVISEL Spectroscopic Phase Modulated Ellipsometer. Accurate and simultaneous determination of thickness and optical properties have been performed in the NIR/Visible range. Similar analyses have been applied to other high-k material such as Ta2O5 / glass, Al2O3 / 3*{A2O3/a-Si} / GaAs, SiO2 / 2*{HfO2 / SiO2) / glass.