19
views
0
recommends
+1 Recommend
0 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: found
      Is Open Access

      Digital holographic microscopy based on a modified lateral shearing interferometer for three-dimensional visual inspection of nanoscale defects on transparent objects

      research-article

      Read this article at

      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          A new type of digital holographic microscopy based on a modified lateral shearing interferometer (LSI) is proposed for the detection of micrometer- or nanometer-scale defects on transparent target objects. The LSI is an attractive interferometric test technique because of its simple configuration, but it suffers from the so-called 'duplicate image’ problem, which originates from the interference of two sheared object beams. In order to overcome this problem, a modified LSI system, which employs a new concept of subdivided two-beam interference (STBI), is proposed. In this proposed method, an object beam passing through a target object is controlled and divided into two areas with and without object information, which are called half-object and half-reference beams, respectively. Then, these two half-beams make an interference pattern just like most two-beam interferometers. Successful experiments with a test glass panel for mobile displays confirm the feasibility of the proposed method and suggest the possibility of its practical application to the visual inspection of micrometer- or nanometer-scale defects on transparent objects.

          Related collections

          Most cited references18

          • Record: found
          • Abstract: found
          • Article: not found

          Digital holography for quantitative phase-contrast imaging.

          We present a new application of digital holography for phase-contrast imaging and optical metrology. This holographic imaging technique uses a CCD camera for recording of a digital Fresnel off-axis hologram and a numerical method for hologram reconstruction. The method simultaneously provides an amplitude-contrast image and a quantitative phase-contrast image. An application to surface profilometry is presented and shows excellent agreement with contact-stylus probe measurements.
            Bookmark
            • Record: found
            • Abstract: found
            • Article: not found

            Living specimen tomography by digital holographic microscopy: morphometry of testate amoeba.

            This paper presents an optical diffraction tomography technique based on digital holographic microscopy. Quantitative 2-dimensional phase images are acquired for regularly-spaced angular positions of the specimen covering a total angle of pi, allowing to built 3-dimensional quantitative refractive index distributions by an inverse Radon transform. A 20x magnification allows a resolution better than 3 microm in all three dimensions, with accuracy better than 0.01 for the refractive index measurements. This technique is for the first time to our knowledge applied to living specimen (testate amoeba, Protista). Morphometric measurements are extracted from the tomographic reconstructions, showing that the commonly used method for testate amoeba biovolume evaluation leads to systematic under evaluations by about 50%.
              Bookmark
              • Record: found
              • Abstract: found
              • Article: not found

              Spatial filtering for zero-order and twin-image elimination in digital off-axis holography.

              Off-axis holograms recorded with a CCD camera are numerically reconstructed with a calculation of scalar diffraction in the Fresnel approximation. We show that the zero order of diffraction and the twin image can be digitally eliminated by means of filtering their associated spatial frequencies in the computed Fourier transform of the hologram. We show that this operation enhances the contrast of the reconstructed images and reduces the noise produced by parasitic reflections reaching the hologram plane with an incidence angle other than that of the object wave.
                Bookmark

                Author and article information

                Contributors
                Journal
                Nanoscale Res Lett
                Nanoscale Res Lett
                Nanoscale Research Letters
                Springer
                1931-7573
                1556-276X
                2014
                4 September 2014
                : 9
                : 1
                : 471
                Affiliations
                [1 ]HoloDigilog Human Media Research Center (HoloDigilog), 3D Display Research Center (3DRC), Kwangwoon University, 447-1 Wolge-Dong, Nowon-Gu, Seoul 139-701, Korea
                Article
                1556-276X-9-471
                10.1186/1556-276X-9-471
                4171088
                c6e6fb12-82cc-4f17-87d7-911671b0e675
                Copyright © 2014 Seo et al.; licensee Springer.

                This is an Open Access article distributed under the terms of the Creative Commons Attribution License ( http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited.

                History
                : 17 July 2014
                : 26 August 2014
                Categories
                Nano Express

                Nanomaterials
                lateral shearing interferometer,digital holographic microscopy,defect detection of transparent materials,three-dimensional visual inspection,depth and phase measurement and metrology

                Comments

                Comment on this article