ABSTRACT
Various problems in experimental mechanics require measurement of very small elements or microregions of large specimens. One of the most popular optical methods, which fulfils these requirements, is high-sensitivity grating interferometry. The wavefront deformations due to out-of-plane displacements have the same value and sign in both interfering beams. Therefore, the influence of out-of-plane displacements is eliminated by the interference. The advantage of this is that the surface layers are inside the head and that it can be easily adjusted by moving one of the mirrors. The efforts toward the production of compact grating interferometry sensors are focused on further miniaturization and simplifying of the design, as well as lowering the production cost. The grating waveguide interferometer can be modified by adding optical elements that form the channel for interferometric shape and out-of-plane displacement measurement. Grating interferometry requires the application on a specimen of a high-frequency reflective-phase type grating.
