Reliable in-line and in-situ measurement of structure of highly polished surfaces remains a major challenge for the modern industry. Evaluation of the wavefront of a scanning laser beam reflected from a surface allows one to establish a direct correlation between the statistics of the optical signal and the surface roughness. Phase structuring of the laser beam greatly increases the height sensitivity down to the nanometer level. High sampling rate allows one to collect a very large number of sampled data and provide a complete analysis of the surface structure rather than a single parameter such as the rms roughness.© (2002) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.