Axial Decorrelation of Paraxial Wavefields: Theory and Experiment

Abstract

Coherent optical systems are widely used in modern non-contact metrology [1]. To understand and design these systems appropriately, it is of utmost importance to be able to relate the optical field at the input of the system to that at the output of the system. Many different models exist for achieving this goal. Here however, we assume that the paraxial approximation is valid for the analysis. The paraxial model generally strikes a reasonable balance between calculating an accurate solution while maintaining a relatively simple description of the physical process. For general speckle metrology systems, consisting of many lenses, Gaussian apertures, and sections of free space, the ABCD-matrix-diffraction approach by Yura et. al. [2] provides an excellent design framework [3].