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Proceedings Paper

Time-gated holographic imaging using photorefractive media
Author(s): Zunaira Ansari; Yan Gu; Mary Tziraki; Duncan Parsons-Karavassilis; Richard Jones; Paul M. W. French; David D. Nolte; Michael R. Melloch
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Paper Abstract

Photorefractive holography is a whole-field, coherence-gating technique for 3-D imaging through turbid media that offers a unique mechanism to discriminate against a background of diffuse light. In contrast to the well-established technique of optical coherence tomography, it is a whole-field imaging technique and may be implemented with light sources of arbitrary spatial coherence, including low cost LEDs and broad-stripe, multimode diode lasers. One drawback of using broadband sources, such as LEDs, for off-axis holographic imaging is the 'walk-off' resulting from the short temporal coherence length that limits the field-of-view. Furthermore, the non-collinear geometry required for off-axis holography can introduce significant image aberration. In this paper we discuss these design considerations for various sources. We have addressed the issue of walk-off for sources of arbitrary bandwidth and have designed an off-axis holographic imaging system based on a Michelson interferometer with a collinear beam geometry that minimizes aberration. In this paper we review our work with high-powered LEDs and discuss these issues associated with spatially incoherent sources. Also, we present a novel, spatially coherent, broadband diode-pumped laser source that may also find application in OCT.

Paper Details

Date Published: 22 November 2000
PDF: 7 pages
Proc. SPIE 4160, Photon Migration, Diffuse Spectroscopy, and Optical Coherence Tomography: Imaging and Functional Assessment, (22 November 2000); doi: 10.1117/12.407606
Show Author Affiliations
Zunaira Ansari, Imperial College of Science, Technology and Medicine (United Kingdom)
Yan Gu, Imperial College of Science, Technology and Medicine (United Kingdom)
Mary Tziraki, Imperial College of Science, Technology and Medicine (United Kingdom)
Duncan Parsons-Karavassilis, Imperial College of Science, Technology and Medicine (United Kingdom)
Richard Jones, Imperial College of Science, Technology and Medicine (United Kingdom)
Paul M. W. French, Imperial College of Science, Technology and Medicine (United Kingdom)
David D. Nolte, Purdue Univ. (United States)
Michael R. Melloch, Purdue Univ. (United States)


Published in SPIE Proceedings Vol. 4160:
Photon Migration, Diffuse Spectroscopy, and Optical Coherence Tomography: Imaging and Functional Assessment
Stefan Andersson-Engels; James G. Fujimoto, Editor(s)

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