Thursday, September 18, 2014

Abstract-Research on object-plane constraints and hologram expansion in phase retrieval algorithms for CW terahertz inline digital holography reconstruction



Jiaqi Hu, Qi Li, and Shanshan Cui
http://www.opticsinfobase.org/ao/upcoming_pdf.cfm?id=217516

In terahertz inline digital holography, the zero-order diffraction light and conjugate image cause reconstructed image misty. In this paper, three phase retrieval algorithms with different object-plane constrain are applied to conduct reconstruction under the same near-field diffraction propagation conditions and image-plane constraint. The impacts of different object-plane constraints on terahertz inline digital holographic reconstruction are studied. The results show that it is not suitable for phase retrieval algorithm to impose restriction on the phase when the object is a little complicated in the terahertz inline digital holography. In addition, the effects of zero-padding expansion, boundary replication expansion and apodization operation on reconstructed images are studied. The results indicate that the conjugate image can be eliminated and a better reconstructed image can be obtained by adopting appropriate phase retrieval algorithm after the normalized hologram extending to the minimum area which meets the applicable range of angular spectrum reconstruction algorithm by means of boundary replication.

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