A phase-shifting vectorial-shearing interferometer with wedge plate phase-shifter

Shape measurement with modified phase-shift lateral shearing interferometry illumination and radial basis function

Three-dimensional shapes of objects were evaluated with modified phase-shift lateral shearing interferometry illumination and radial basis function. A simple optical system was developed to create the fringe pattern based on the Murty interferometer. The phase shift was generated only by moving a plane-parallel plate along an in-plane parallel direction. A novel moving radial basis function method was presented to improve the quality of fringe patterns. And the proper calculation window size was given based on numerical simulation. Three-dimensional shapes of two kinds of objects were determined to verify the feasibility and effectiveness of the proposed method, and the reconstructed height distributions were in good accordance with the referenced data.

Phase-shifting lateral shearing interferometry using wedge-plate and interferometric grating

A simple and robust method for introducing a phase-shifting test procedure in a wedge-plate shearing interferometer is proposed. The output of the wedge-plate lateral shearing interferometer (LSI) is superposed onto a sinusoidal grating, forming a moiré pattern. The in-plane translation of grating perpendicular to the grating lines is used for introducing a known amount of phase shifts in the interferometer. Direct measurement of phase using a four-step phase-shifting method is undertaken. The applicability of this devised phase-shifting wedge-plate LSI has been successfully tested for setting the collimation position of optical beams. Good accuracy and precision are achieved.