Angle Resolved Light Scattering Microscope

Stray light in optical systems caused by surface roughness or defects of the optical components can lead to critical degradation of the image quality. The need for high precision optical components in the space and lithography industry necessitates the characterization of scattered light from each component. Hence, highly sensitive angle resolved scattering measurement instruments for roughness and defect characterization of optical components have been developed at Fraunhofer IOF. On the other hand, the growing demand for high precision micro-optical components such as digital micromirror devices and microlens arrays requires novel metrology solutions with smaller field of measurement within the micrometer range. To meet this need, we propose a lens based optical setup employing the confocal principle for the instantaneous measurement of angle resolved scattering distribution from a microscopic field of view on the component surface. This approach is also valuable for measuring the scattering phase function of biological tissues at microscopic resolution.