Complex object wave extraction using time-multiplexing in off-axis digital holography

Abstract

In this paper, we present an algorithm for complex object wave extraction in off-axis digital holography using a time-multiplexing and frequency spectrum-shifting technique. The proposed approach utilizes the digital time-multiplexing technique, in which two 90-deg-rotated off-axis holograms are recorded in sequence, and corresponding spectra are subtracted in the computed Fourier domain to eliminate the DC term. Then, the two subtracted holograms are digitally multiplexed into one complex hologram in the same plane, and by shifting the spatial frequency spectra of the subtracted hologram in the spatial frequency domain, one of the two cross-correlations can be obtained in the center. This technique simply extracts the spectrum of the real image in the frequency domain than the spatial filtering method.

Zero-order-removal off-axis digital holographic reconstruction using different beam-ratio holographic recordings

“…19,20 In the other way, by sequentially recording two holograms with orthogonal stripes each other by time-multiplexing, the zero-order elimination can be achieved by their subtraction in the spatial frequency domain. 21 In addition, the zero-order and conjugate terms of an off-axis hologram can be suppressed using singular value decomposition in adaptive filtering. 22 In this paper, we present a method of the zero-order-term removal for off-axis digital holographic reconstruction by three holographic recordings with different beam-splitting ratios.…”

“…Either of a numerical iteration method without prior knowledge of the target or a spatial domain iteration algorithm is also used to eliminate the zero-order term in digital holography 19 , 20 . In the other way, by sequentially recording two holograms with orthogonal stripes each other by time-multiplexing, the zero-order elimination can be achieved by their subtraction in the spatial frequency domain 21 . In addition, the zero-order and conjugate terms of an off-axis hologram can be suppressed using singular value decomposition in adaptive filtering 22 …”