Extension of the controlled sensitivity range in holographic interferometry with a lateral shear

The possibility of controlling the measurement sensitivity in shearing interferometry with a small lateral shear is considered. A method based on recording several holographic interferograms with different magnitudes of lateral shear and with different carrier frequencies of holographic fringes during a single exposure is proposed. The measurement sensitivity of the interference patterns is controlled at the stage of optical processing of the combined holographic interferograms with lateral shear, when the interferograms are illuminated by two coherent light beams and the filtering of the corresponding diffraction orders is performed. The results of the experimental testing of the proposed method by using it for the visualization of the melting zones of planar polymethylmethacrylate samples under heat treatment are presented.