Radial-shearing digital holography has been proposed to reconstruct the wavefront of test object in a common path, which can take use of a bifocal diffractive lens to realize radial-shearing interference. For coherent light source, the recording plane is usually located near the focal point in order to reduce the crosstalk. As for incoherent light source, on the one hand, the above recording cannot take advantage of the space-bandwidth product of optical detector, and on the other, the optical path length is far greater than the coherent length of the light source, which results in failure of effective interferogram. A high contrast interferogram must meet the requirement of nearly equal intensity between the two interference beams. Based on this viewpoint, a better recording plane for radial-shearing holography is in the middle location between the two images. Compared to the recording location with equal beam diameter, the midpoint of the two images is a better choice to improve the image quality on condition that one focal length is much greater than the other. Otherwise, this difference will gradually decrease as one focus is close to the other. The experiment was carried out to verify the validity of our proposed method.
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