A Nonlinear Technique for Automatic Twin-Image and Zero-Order Term Suppression in Digital Holographic Microscopy

Digital holography enables the encoding of complex wavefronts with an intensity measurement, making it possible to recover the quantitative phase for phase-contrast imaging [1] or profilometry [2]. Encoding the wavefront in this fashion leads, however, to the generation of artifacts such as the socalled zero-order, which is the sum of the intensities of the object and reference waves, and the so-called twin-image, which corresponds to the complex conjugate of the desired imaging order. Since the first developments, efforts have been made to suppress the artifacts either by separation in the spatial Fourier domain in the so-called off-axis configuration [3], or by temporal separation through phaseshifting algorithms [4]. The spatial separation method has the advantage of making it possible to reconstruct the hologram from a single measurement, but at the cost of loss of bandwidth for the imaging terms. We propose here a technique based on non-linear filtering to suppress the zero-order artifact for off-axis digital holographic microscopy (DHM). The advantages of the proposed method are: (1) it can potentially increase the spatial bandwidth for the imaging terms; (2) it is non-iterative; and (3) it keeps the one-shot feature of DHM.