Suppression of moire patterns in digital holography

Digital holography, which utilizes semiconductor sensors rather than sensitized films as the recording medium, is a very attractive and convenient approach in today\u27s holography technology. On one hand, coherent interference holograms usually contain high spatial frequency fringes as part of the phase information. On the other hand, the spatial resolution of digital holography is restricted by the limitations of imaging devices, such as the pixel size. The Moire effect, a pattern deformation effect emerging from image under-sampling, occurs and vitiates the quality of the reconstructed image. In this work, the formation of Moire patterns, which is the result of Moire effect, is systematically studied in both Fresnel and Fraunhofer regions. Quantitative descriptions of Moire patterns are established for both plane wave source and point source holography. Experimental results show that the locations of Moire patterns can be predicted with high accuracy. Meanwhile, both theoretical analysis and experiments demonstrate that ultra-short pulse illumination can be utilized to eliminate Moire patterns efficiently. Moreover, the formation of Moire patterns in imaging systems under the influence of aberrations is studied. Quantitative descriptions are also established. The potential application of Moire patterns in the determination of aberration for imaging systems is also proposed