Characterization of profilograms of piecewise-continuous diffraction microrelief

Questions of the profilometric analysis of the piecewise-continuous microrelief of high-efficiency diffraction elements have been virtually ignored in the literature, even though the market for diffraction optics has substantially increased in recent years, and high-efficiency diffraction elements have gone from the realm of the exotic to ordinary practice of optical instrumentation. In this paper, the authors consider several techniques for evaluating microrelief that make it possible to compute the “approximated depth,” almost regardless of the type of profilometer being used. The proposed techniques are based on a polynomial approximation of the diffraction-zone profile with minimization of the influence of the unreliable data close to its boundaries.