Scanning holographic microscopy with resolution exceeding the Rayleigh limit of the objective by superposition of off-axis holograms

Department of Physics, Virginia Tech, Blacksburg, Virginia 24061-0435, USA.
Applied Optics (Impact Factor: 1.78). 03/2007; 46(6):993-1000. DOI: 10.1364/AO.46.000993
Source: PubMed


We present what we believe to be a new application of scanning holographic microscopy to superresolution. Spatial resolution exceeding the Rayleigh limit of the objective is obtained by digital coherent addition of the reconstructions of several off-axis Fresnel holograms. Superresolution by holographic superposition and synthetic aperture has a long history, which is briefly reviewed. The method is demonstrated experimentally by combining three off-axis holograms of fluorescent beads showing a transverse resolution gain of nearly a factor of 2.

Download full-text


Available from: Joseph Rosen
  • Source
    • "Incoherent [1,2] and partially coherent [3] digital holographic microscopies have recently become fields of much interest because of the ability of microscopes based on these principles to image three dimensional (3D) incoherent objects. In addition, some of these systems are capable of imaging fluorescent labeled specimens [1,2], while others can perform sectioning of the 3-D observed volume [4]; and some have even demonstrated improvement in resolution by operating in synthetic aperture mode [5]. More recently, a lensless version of a partially coherent [3], digital holographic microscope has been installed on-chip in a very compact configuration. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Fresnel Incoherent Correlation Holography (FINCH) enables holograms and 3D images to be created from incoherent light with just a camera and spatial light modulator (SLM). We previously described its application to microscopic incoherent fluorescence wherein one complex hologram contains all the 3D information in the microscope field, obviating the need for scanning or serial sectioning. We now report experiments which have led to the optimal optical, electro-optic, and computational conditions necessary to produce holograms which yield high quality 3D images from fluorescent microscopic specimens. An important improvement from our previous FINCH configurations capitalizes on the polarization sensitivity of the SLM so that the same SLM pixels which create the spherical wave simulating the microscope tube lens, also pass the plane waves from the infinity corrected microscope objective, so that interference between the two wave types at the camera creates a hologram. This advance dramatically improves the resolution of the FINCH system. Results from imaging a fluorescent USAF pattern and a pollen grain slide reveal resolution which approaches the Rayleigh limit by this simple method for 3D fluorescent microscopic imaging.
    Full-text · Article · Mar 2011 · Optics Express
  • Source
    • "Therefore, the use of this technique is limited only to those applications in which the observed targets can be illuminated by a laser. Synthetic aperture carried out by a combination of several off-axis incoherent holograms in scanning holographic microscopy has been demonstrated by (Indebetouw et al., 2007). However, this method is limited to microscopy only, and although it is a technique of recording incoherent holograms, a specimen should also be illuminated by an interference pattern between two laser beams. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Holographic imaging offers a reliable and fast method to capture the complete threedimensional (3D) information of the scene from a single perspective. However, holography is not widely applied to the regime of white-light imaging, because white-light is incoherent and in general creating holograms requires a coherent interferometer system. In this chapter
    Full-text · Chapter · Feb 2011
  • Source
    • "Finally, all the propagated distributions are used to assemble a synthetic expanded aperture that yields a superresolved image by Fourier transformation. Thus, and in summary, the whole proposed procedure could be understood as a technique based on time multiplexing the spatial-frequency content diffracted by the input sample in a similar way to that which sequential off-axis illumination performs in digital holographic microscopy [29] [30] [31] [32] [33] [34] [35] [36], but where the synthetic aperture is generated by CCD displacement [23] [24] [25] [26] [27] [28]. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Holography in the Gabor regime is restricted to weak diffraction assumptions. Otherwise, diffraction prevents an accurate recovery of the object's complex wavefront. We have recently proposed a modified Gabor-like setup to extend Gabor's concept to any sample provided that it be non-diffusive. However, the resolution of the final image becomes limited as a consequence of the additional elements considered in the proposed setup. In this paper we present an experimental approach to overcome such a limitation in which the former configuration is used while the CCD camera is shifted to different off-axis positions in order to generate a synthetic aperture. Thus, once the whole image set is recorded and digitally processed for each camera position, we merge the resulting band-pass images into one image by assembling a synthetic aperture. Finally, a superresolved image is recovered by Fourier transformation of the information contained in the generated synthetic aperture. Experimental results validate our concepts for a gain in resolution of close to 2.
    Full-text · Article · Sep 2009 · Journal of Optics A Pure and Applied Optics
Show more