Interferometric Measurements of Surface Topography
Featured Product from Zygo Corporation
Many ZYGO metrology instruments rely on interferometry combined with imaging systems to measure surface form, waviness, and roughness. Although these instruments have advanced software that performs data interpretation for you, it can be helpful to understand how the imaging process influences interferometric measurements at a fundamental level. This understanding can help in optimizing measurement setups, for example, in choosing the appropriate microscope objective for 3D optical profilers given surface slopes, and the minimum detectable feature separation for a given numerical aperture.
ZYGO has developed an interactive demonstrator using a simple Excel worksheet that uses standard spreadsheet functions to simulate the response of a highly simplified interferometer. While the demonstrator is not intended to replace careful applications development or to perfectly predict what is seen in real measurements with advanced hardware and software, it is an engaging and easy-to-use approach to learning about the fundamentals of interferometric measurements of surface topography.
Here are the links to the interactive demonstrator and supporting materials:
- Elementary Fourier Optics Model for Interferometric Measurements of Surface Topography (interactive demonstrator, Excel document)
- "How To" video for the above interactive demonstrator
- Video tutorial on the theory of the interactive demonstrator
(from the 2020 SPIE Optics and Photonics Digital Forum)
- Fourier optics modelling of instrument response for interference microscopy (Technical Paper)