Abstract: An optical measuring system includes a scatterometer in which an illumination beam is provided through an aperture in a lens used to collect light for the scattering detection. The void may be a slit in the lens, a missing portion along an edge of the lens, or another suitable void. Another detection channel may be provided to detect light returning through the void in the collecting lens, for example, a profilometer may be implemented by detecting interference between reflected light returning along the illumination path and light from the illumination source.

Abstract: An optical surface inspection system provides dark-field detection avoiding ghost images and without capturing, stray, reflected or re-scattered light. The system includes an illumination system that generates an illumination spot on a surface under inspection collecting lens that collects substantially all light scattered from the surface under inspection from the illumination spot. The system also includes a light guide with a first end having a numerical aperture matched to an exit aperture of the collecting lens and a field of view matched to the illumination spot, and a second end coupled to a detector.