Measurements of angular and spectral resolved scattering on complex optical coatings

Due to market demand and technical progresses, a new generation of optical components requires much more sophisticated structures with a great number of layers. These complex structures enable to achieve severe optical performances but, at the same time, enhance light scattering processes. For these reasons, it is essential to develop a metrological tool which provides an accurate quantification of the spectral and angular scattering losses behavior with sufficient angular and spectral resolutions. In order to face this issue, new investigations were performed by our group at Institut Fresnel and led to the development of the new scatterometer SALSA (Spectral and Angular Light Scattering characterization Apparatus). The use of both a broad-band light source and a tunable filter allows to accurately select the illumination wavelength and the spectral bandwidth on the whole spectral range of CCD detectivity. In this paper we will present the performances of the setup and some experimental results.