Optical surface profilometry of low reflectance materials – Evaluation as a laser processing diagnostic

Optical surface profilometry is a technique that has advantages over other Profilometry techniques (stylus Profilometry, AFM) of being non-contact and being able to profile comparatively large areas in a single “z-scan”. Thus, it is employed in monitoring surface quality and measuring surface form in high technology manufacturing processes and quality assurance, as well as in research and development contexts. Its application to optical materials has been limited due to issues relating to the low reflectance of the surfaces. Results of a feasibility study for profiling laser induced optical damage and “loose” microscopic sized pieces of optical material (either debris or particles introduced by design) on optical substrates, will be reported. Progress on developing successful strategies for making quantitative measurements on these difficult samples has been achieved.