A phase-shifting electronic speckle pattern shearing interferometer with a very simple shearing device is proposed. Two partially reflective glass plates are used to introduce the shear in this new interferometer. The reflection coefficients of the coatings were 0.3 and 0.7 respectively. The distance between the two glass plates controls the size of the shear. The proposed new interferometric system is simple, flexible and low cost. OCIS codes: 120.6160 Speckle interferometry; 220.4830 Optical

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... ystems design Electronic speckle pattern shearing interferometry (ESPSI) enables direct measurements of displacement derivatives to be made with variable sensitivity 1-2 . A common lateral shear interferometer uses a plane parallel glass plate as a shearing device. The amount of shear is selected by the thickness and tilt of the plate 3 . The disadvantages of this simple shearing interferometer are that the resulting interferogram has low fringe visibility and phase-shifting techniques can not be applied. Phase-shifting shearography is more sensitive than the simple Maurice Whelan,