Light scattering and atomic force microscopic investigations on magnetron sputtered oxide single layers and multilayers for micromechanical laser mirrors
Oxide single layers of niobium oxide and silicon dioxide with different film thicknesses and multilayers consisting of this both components were deposited by reactive sputtering on silicon substrates. The loss of optical performance by structural imperfections was characterized measuring the total light scattering in comparison to AFM roughness investigations. The measured scattered light and the rms roughness values calculated from the AFM images were found to correlated clearly with the density of macroscopic defects in the Nb2O5 and SiO2 single layers. With multilayers, similar effects were observed.