Interferometers for the measurement of surface form and texture have a reputation for high performance. However, the results for many types of surface features can deviate from the expectation of one cycle of phase shift per half wavelength of surface height. Here we review the fundamentals of imaging interferometry and describe ways of defining instrument response, including the linear instrument transfer function. These considerations define practical regimes of linear behavior that are usually satisfied for traditional uses of interferometers; but that are increasingly challenged by applications involving complex textures and high surface slopes. We conclude by proposing pathways for further improving performance on difficult surface structures using advanced modeling techniques.

Date Published: 3 September 2019
PDF: 11 pages
Proc. SPIE 11102, Applied Optical Metrology III, 111020G (3 September 2019); doi: 10.1117/12.2526654

Published in SPIE Proceedings Vol. 11102:
Applied Optical Metrology III
Erik Novak; James D. Trolinger, Editor(s)