The optical properties of micron- or submicron-sized particles can be different in a significant way compared to the properties of a bulk sample of the same material. This is especially true for particles comparable in size to the wavelength of the radiation under consideration. Besides determining mean values for optical constants for an ensemble of such small particles, e.g. by using effective medium theory, especially the angle-dependent light scattering is influenced by the shape and structure of the particles. There is a sensitive dependence of the polarization and intensity of scattered light on the particle shape. In a variety of cosmic environments dust particles are expected to be very complex in structure. Their morphology might nevertheless be described and understood by the concepts of fractal physics. However, they differ from spheres and, therefore, rather poor predictions for their optical properties can be given nowadays. The understanding of the light scattering is essential for the physics of these environments, e.g. by influencing radiation transport or for interpretation of observations, e.g. of dichroic extinction, which might trace magnetic fields and even particle-gas flows. The proposed project aims to determine the light scattering of relevant fractal aggregates experimentally.