Purely numerical compensation for microscope objective phase curvature in digital holographic microscopy: Inuence of digital phase mask position.

Ecole Polytechnique Fédérale de Lausanne (EPFL), Institut d'Optique Appliquée, Ch-1015 Lausanne, Switzerland.
Journal of the Optical Society of America A (Impact Factor: 1.56). 12/2006; 23(11):2944-53. DOI: 10.1364/JOSAA.23.002944
Source: PubMed


Introducing a microscope objective in an interferometric setup induces a phase curvature on the resulting wavefront. In digital holography, the compensation of this curvature is often done by introducing an identical curvature in the reference arm and the hologram is then processed using a plane wave in the reconstruction. This physical compensation can be avoided, and several numerical methods exist to retrieve phase contrast images in which the microscope curvature is compensated. Usually, a digital array of complex numbers is introduced in the reconstruction process to perform this curvature correction. Different corrections are discussed in terms of their influence on the reconstructed image size and location in space. The results are presented according to two different expressions of the Fresnel transform, the single Fourier transform and convolution approaches, used to propagate the reconstructed wavefront from the hologram plane to the final image plane.

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    • "The main objective of this study is to experimentally investigate the tendency of therapeutic platelet substitute to aggregate under real blood conditions using digital holographic microscopy. A new application of holography in the field of optical microscopy has introduced a new imaging technology, known as digital holographic microscopy [4]. Based on the principle of coherence imaging, it allows reconstruction of a three-dimensional (3D) volumetric field from a single hologram capture. "
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    Optics and Lasers in Engineering 05/2015; 68. DOI:10.1016/j.optlaseng.2014.12.011 · 2.24 Impact Factor
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    • "This means that provided that the optical elements in the image half space remain unchanged , this calibration will therefore remain valid even if the object half space is modified (object and object location, direction and curvature of the illumination beam). The reconstruction methods mentioned above [11] [12] [13] [14] [15] made reconstruction in the image half space. This means that the image of the object in plane O is reconstructed by propagating the hologram over a distance d from C to O. "
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    ABSTRACT: We propose a holographic microscopy reconstruction method, which propagates the hologram, in the object half space, in the vicinity of the object. The calibration yields reconstructions with an undistorted reconstruction grid i.e. with orthogonal x, y and z axis and constant pixels pitch. The method is validated with an USAF target imaged by a x60 microscope objective, whose holograms are recorded and reconstructed for different USAF locations along the longitudinal axis:-75 to +75 {\mu}m. Since the reconstruction numerical phase mask, the reference phase curvature and MO form an afocal device, the reconstruction can be interpreted as occurring equivalently in the object or in image half space.
    Applied Optics 05/2015; 54(15):4672. DOI:10.1364/AO.54.004672 · 1.78 Impact Factor
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    • "To reconstruct the object image, we use an algorithm based on the diffraction scalar theory, Fresnel approximation [19] [20] [21] [22]. We follow the standard procedure [23] with steps which include: Fourier transform to separate the twin images, Fresnel transform to reconstruct the object image from the +1 order, correction for tilt and spherical aberrations, numerical focalization. "
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    ABSTRACT: In this paper, we present our results obtained using an interferometric technique to investigate a constant thickness sample, which presents inside regions with different values for the refractive index. The sample is prepared on a polycarbonate (PC) substrate. On its surface, some microstructures are imprinted using controlled values for temperature and forces, after we determined experimentally the value of the temperature for glass transition. These microstructures were then filled with an epoxy resin. Using the images acquired experimentally, we computed the phase shift map introduced by the sample in the optical path. It is proportional with the geometrical height of the microstructures and with the difference between the refractive indices of the polycarbonate and the epoxy resin. In this way, we find the phase shift profile inside of a transparent thin film of a sample with plane parallel surfaces.
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