The art of characterizing light scattering from optical components and systems

Even high-end optical components exhibit small amounts of imperfections, which can easily limit the performance of optical systems with respect to imaging contrast, optical throughput, imaging ghosts, and increased light scattering. Characterizing the scattering properties of optical components is thus an important step during the development of sophisticated optical systems as well as to identify and steadily improve materials as well as manufacturing and assembling steps. This is illustrated for different optical components as well as optical systems. Furthermore, different characterization concepts are discussed, which allow overcoming typical limits for angles resolved light scattering measurements, such as scattering very close to the specular beam directions (off specular scattering angles < 0.1°) or measurements in retro-reflection, which are important for gratings used in Littrow configuration or optical mirrors for laser-based communication.