Speckle shear interferometry, or shearography, has been more and more frequently used in the industry for in-field nondestructive inspections of flaws in composite materials used in the aerospace and oil and gas industry. Nowadays new applications has emerged demanding the ability to operate in harsher environments. Bringing interferometric systems to harsh environments is not an easy task since they are very sensitive to many harsh environmental factors. Due to the quasi-equal-path property, shearography is an intrinsically robust interferometric technique that has been successfully used in the field, but there are still limits to overcome. Mechanical vibrations are probably the most challenging factor to cope in the field measurements. This work presents a potentially robust shear interferometer configuration. It uses a Wollaston prism as the shearing element rather than a traditional Michelson interferometer and polarizers to achieve the phase shift. The use of the Wollaston prism makes the optical setup more compact and robust, given that a rotating polarizer is the only movable part of the interferometer.

Date Published: 28 August 2016
PDF: 6 pages
Proc. SPIE 9960, Interferometry XVIII, 996015 (28 August 2016); doi: 10.1117/12.2237395

Published in SPIE Proceedings Vol. 9960:
Interferometry XVIII
Katherine Creath; Jan Burke; Armando Albertazzi Gonçalves Jr., Editor(s)