One dimensional surface profilometry by analyzing the Fresnel diffraction pattern from a step

When a coherent quasi-monochromatic light is reflected from a step, a diffraction pattern is formed that can be described by Fresnel-Kirchhoff integral and visibility of the fringes depends on the height of the step. In this paper, it is shown that the Fresnel diffraction from a step can be described by an interference-like formula. A relationship is derived between the visibility of the diffraction pattern from 1D step and the step height. Finally, a novel method is presented for 1D surface testing. The theoretical and experimental results are presented.