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Volume 2017 (2017), Article ID 7293905, 7 pages
https://doi.org/10.1155/2017/7293905
Research Article

Manipulations of Wavefront Propagation: Useful Methods and Applications for Interferometric Measurements and Scanning

1Department of Applied Physics/Electro-Optics Engineering, Faculty of Engineering, Lev Academic Center, 9116001 Jerusalem, Israel
2Shlonsky St. 31, 69400 Tel Aviv, Israel

Correspondence should be addressed to Avi Karsenty

Received 5 April 2017; Revised 29 June 2017; Accepted 20 July 2017; Published 21 August 2017

Academic Editor: Richard Arinero

Copyright © 2017 Avi Karsenty et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Phase measurements obtained by high-coherence interferometry are restricted by the 2π ambiguity, to height differences smaller than λ/2. A further restriction in most interferometric systems is for focusing the system on the measured object. We present two methods that overcome these restrictions. In the first method, different segments of a measured wavefront are digitally propagated and focused locally after measurement. The divergent distances, by which the diverse segments of the wavefront are propagated in order to achieve a focused image, provide enough information so as to resolve the 2π ambiguity. The second method employs an interferogram obtained by a spectrum constituting a small number of wavelengths. The magnitude of the interferogram’s modulations is utilized to resolve the 2π ambiguity. Such methods of wavefront propagation enable several applications such as focusing and resolving the 2π ambiguity, as described in the article.