Comparison Of Techniques For Measuring The Roughness Of Optical Surfaces

Instrumental techniques available for measuring the roughness of optical surfaces include mechanical profilometers and optical heterodyne profilometers, both of which yield surface profiles, and total integrated and angle-resolved scattering, from which roughness values can be derived using appropriate theoretical relations. These methods are used to measure the roughness of a set of roughness standards made by polishing ground Zerodur surfaces for progressively longer times. The measured roughnesses are compared, and the reasons for the differences are discussed.