Abstract

Displacement measurements by optical interferometry are affected by errors in the determination of the phase-difference and in interferometer sensitivity. In this paper, we perform an uncertainty analysis of displacements measured by inplane ESPI with spherical wavefronts. The displacements were induced by applying uniaxial tensile load on a nominally flat elastic sample. Our attention was focused on the quantification of the effect of eventual errors in the sensitivity vector determination. We found that the displacement uncertainty depends on the geometry of the optical arrangement, and on the dimensions of the illuminated field. Moreover, the displacement uncertainty increases with the deformation.