Correct self-assembling of spatial frequencies in super-resolution synthetic aperture digital holography

CNR-Istituto Nazionale di Ottica Applicata, via Campi Flegrei 34, 80078 Pozzuoli (NA) Italy.
Optics Letters (Impact Factor: 3.18). 12/2009; 34(23):3650-2. DOI: 10.1364/OL.34.003650
Source: PubMed

ABSTRACT Synthetic aperture enlargement is obtained, in lensless digital holography, by introducing a diffraction grating between the object and the CCD camera with the aim of getting super-resolution. We demonstrate here that the spatial frequencies are naturally self-assembled in the reconstructed image plane when the NA is increased synthetically at its maximum extent of three times. By this approach it possible to avoid the use of the grating transmission formula in the numerical reconstruction process, thus reducing significantly the noise in the final super-resolved image. Demonstrations are reported in 1D and 2D with an optical target and a biological sample, respectively.

Download full-text


Available from: Pietro Ferraro, Jul 28, 2015
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: In analog holography, the infrared (IR) range received quite some attention, since it could provide interesting information, not achievable otherwise. Since digital sensors in this band became recently available and affordable, also digital holography (DH) expanded its feasibility beyond the visible wavelengths. In fact, the IR range allows shorter recording distances, unparalleled larger field of view and less stringent requirements on system stability, together with some specific characteristics, like e.g. the possibility to test IR glasses or other materials transparent to IR radiation, which cannot be controlled in visible range. In this paper we review the activities which took place in this field and illustrate the results achieved, referring to the opportunities this technique offers, and the challenges it presents. We show efficient reconstructions of holograms of objects of various materials, recorded with different resolution digital thermal cameras, in various configurations, and moreover we demonstrate optical holographic display through a liquid crystal based Spatial Light Modulator which gives the chance to get direct 3D imaging and display of long IR range. Moreover we believe this opens the route toward holography in THz region. Keywordsdigital holography–infrared radiation–thermal camera–infrared testing
    01/2010; 1(4):1-10. DOI:10.1007/3DRes.04(2010)06
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We propose a real-time digital holographic microscopy, that enables simultaneous multiple reconstructed images with arbitrary resolution, depth and positions, using Shifted-Fresnel diffraction instead of Fresnel diffraction. In this system, we used four graphics processing units (GPU) for multiple reconstructions in real-time. We show the demonstration of four reconstruction images from a hologram with arbitrary depths, positions, and resolutions.
    Journal of optics 01/2010; 12(6). DOI:10.1088/2040-8978/12/6/065402 · 2.01 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: In this Letter we report on an alternative approach to get multiple images in microscopy, exploiting the capabilities of both a lithium niobate diffraction grating and digital holographic technique. We demonstrate that multi-imaging can be achieved in a lensless configuration by using a hexagonal diffraction grating but overcoming, thanks to digital holography (DH), the many constrains imposed by the grating parameters in multi-imaging with Talbot effect or Talbot array illuminators. In fact, DH permits the numerical reconstruction of the optical field diffracted by the grating, thus obtaining in-focus multiple images in a plane different from the fractional or entire Talbot ones.
    Optics Letters 04/2010; 35(7):1010-2. DOI:10.1364/OL.35.001010 · 3.18 Impact Factor
Show more