Over the past few years temporal phase-shifting interferometry has emerged as an efficient technique for non-destructive metrological applications. Shearography, or speckle shearing interferometry, is a full field non-contact optical technique generally used for the measurement of the gradient of the displacement of a loaded surface. In our laboratory, an original setup for digital phase-shifting shearography has been developed. The key element of the experimental setup is the shearing device, a prism with a coating and a thin glass attached plate that separates the two TE and TM polarization modes. This shearing device yields an almost-common path and an in-line configuration of the shearing interferometer, an arrangement that leads to a compact device that is little sensitive to external disturbances. The efficiency of this experimental setup has been proved for different applications in mechanics and biophotonics.
Phase maps obtained by speckle interferometry (left) and shearography (right)