Displacement measurement along a line by the diffractographic method

The diffractographic method, a recently developed experimental technique, has been extended to solve the problem of determining the displacement information along the length of a beam. The method, which uses the diffraction of monochromatic light through a variable aperture whose size is a function of the beam displacement, demonstrates that this displacement along a line technique offers a new and accurate method occupying the unique position between point detectors and whole-field procedures.