Reflections about holographic and non-holographic acquisition of surface topography

TL;DR

This paper compares holographic and non-holographic methods for surface topography measurement, analyzing their fundamental principles, precision limits, and how topographic data is encoded and decoded, to guide users in optimizing measurement accuracy.

Contribution

It provides a comprehensive comparison of holographic and traditional optical metrology techniques, clarifying their fundamental differences and similarities for surface topography measurement.

Findings

Holography and interferometry have different physical origins affecting precision.

The encoding and decoding of topographic information differ between methods.

Understanding these differences helps optimize measurement accuracy.

Abstract

Recording and (computational) processing of complex wave fields offers a vast realm of new optical methods. Also for optical 3D-metrology. We discuss fundamental similarities and differences of holographic surface topography measurement versus non-holographic principles, such as triangulation, classical interferometry, rough surface interferometry and slope measuring methods. Key features are the physical origin of the ultimate precision limit and how the topographic information is encoded and decoded. We demonstrate that the question "is holography just interferometry?" has different answers, depending on how we exploit holograms or interferograms for metrology. The answers will help users to find out if their measurement results could be improved or if they already hit the ultimate limit of what physics allows.