1. Articles from Peng Xiao

    1-9 of 9
    1. In vivo imaging through the entire thickness of human cornea by full-field optical coherence tomography

      In vivo imaging through the entire thickness of human cornea by full-field optical coherence tomography

      Despite obvious improvements in visualization of the in vivo cornea through the faster imaging speeds and higher axial resolutions, cellular imaging stays unresolvable task for OCT, as en face viewing with a high lateral resolution is required. The latter is possible with FFOCT, a method that relies on a camera, moderate numerical aperture (NA) objectives and an incoherent light source to provide en face images with a micrometer-level resolution. Recently, we for the first time demonstrated the ability of FFOCT to capture images from the in vivo human cornea1. In the current paper we present an extensive study of appearance ...

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    2. In vivo high resolution human corneal imaging using full-field optical coherence tomography

      In vivo high resolution human corneal imaging using full-field optical coherence tomography

      We present the first full-field optical coherence tomography (FFOCT) device capable of in vivo imaging of the human cornea. We obtained images of the epithelial structures, Bowman’s layer, sub-basal nerve plexus (SNP), anterior and posterior stromal keratocytes, stromal nerves, Descemet’s membrane and endothelial cells with visible nuclei. Images were acquired with a high lateral resolution of 1.7 µm and relatively large field-of-view of 1.26 mm x 1.26 mm – a combination, which, to the best of our knowledge, has not been possible with other in vivo human eye imaging methods. The latter together with a contactless ...

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    3. Retinal imaging with adaptive optics full-field OCT

      Retinal imaging with adaptive optics full-field OCT

      Adaptive optics full-filed OCT (FFOCT) with a transmissive liquid crystal spatial light modulator (LCSLM) as wavefront corrector is used without strict plane conjugation for low order aberrations corrections. We validated experimentally that FFOCT resolution is independent of aberrations and only reduce the signal level. A signal based sensorless algorithm was thus applied for wavefront distortion compensation. Image quality improvements by the wavefront sensorless control of the LCSLM were evaluated on in vitro samples. By replacing the FFOCT sample arm objective with an artificial eye used to train ophthalmologists, adaptive optics retinal imaging was achieved. In vivo experiments using a liquid ...

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    4. En face coherence microscopy [Invited]

      En face coherence microscopy [Invited]

      En face coherence microscopy or flying spot or full field optical coherence tomography or microscopy (FF-OCT/FF-OCM) belongs to the OCT family because the sectioning ability is mostly linked to the source coherence length. In this article we will focus our attention on the advantages and the drawbacks of the following approaches: en face versus B scan tomography in terms of resolution, coherent versus incoherent illumination and influence of aberrations, and scanning versus full field imaging. We then show some examples to illustrate the diverse applications of en face coherent microscopy and show that endogenous or exogenous contrasts can add ...

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    5. Adaptive optics full-field optical coherence tomography

      Adaptive optics full-field optical coherence tomography

      We describe a simple and compact full-field optical coherence tomography (FFOCT) setup coupled to a transmissive liquid crystal spatial light modulator (LCSLM) to induce or correct aberrations. To reduce the system complexity, strict pupil conjugation was abandoned because low-order aberrations are often dominant. We experimentally confirmed a recent theoretical and experimental demonstration that the image resolution was almost insensitive to aberrations that mostly induce a reduction of the signal level. As a consequence, an image-based algorithm was applied for the optimization process by using the FFOCT image intensity as the metric. Aberration corrections were demonstrated with both an USAF resolution ...

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    6. Full-field spatially incoherent illumination interferometry: a spatial resolution almost insensitive to aberrations

      Full-field spatially incoherent illumination interferometry: a spatial resolution almost insensitive to aberrations

      We show that with spatially incoherent illumination, the point spread function (PSF) width/spatial resolution of an imaging interferometer like that used in full-field optical coherence tomography (OCT) is almost insensitive to aberrations. In these systems, aberrations mostly induce a reduction of the signal level that leads to a loss of the signal-to-noise ratio without broadening the system PSF. This is demonstrated by comparison with traditional scanning OCT and wide-field OCT with spatially coherent illuminations. Theoretical analysis and numerical calculation as well as experimental results are provided to show this specific merit of incoherent illumination in full-field OCT. To the ...

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    7. In vivo wide-field reflectance/fluorescence imaging and polarization-sensitive optical coherence tomography of human oral cavity with a forward-viewing probe

      In vivo wide-field reflectance/fluorescence imaging and polarization-sensitive optical coherence tomography of human oral cavity with a forward-viewing probe

      We report multimodal imaging of human oral cavity in vivo based on simultaneous wide-field reflectance/fluorescence imaging and polarization-sensitive optical coherence tomography (PS-OCT) with a forward-viewing imaging probe. Wide-field reflectance/fluorescence imaging and PS-OCT were to provide both morphological and fluorescence information on the surface, and structural and birefringent information below the surface respectively. The forward-viewing probe was designed to access the oral cavity through the mouth with dimensions of approximately 10 mm in diameter and 180 mm in length. The probe had field of view (FOV) of approximately 5.5 mm in diameter, and adjustable depth of field (DOF ...

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    8. Gradient index lens based combined two-photon microscopy and optical coherence tomography

      Gradient index lens based combined two-photon microscopy and optical coherence tomography

      We report a miniaturized probe-based combined two-photon microscopy (TPM) and optical coherence tomography (OCT) system. This system is to study the colorectal cancer in mouse models by visualizing both cellular and structural information of the colon in 3D with TPM and OCT respectively. The probe consisted of gradient index (GRIN) lenses and a 90° reflecting prism at its distal end for side-viewing, and it was added onto an objective lens-based TPM and OCT system. The probe was 2.2 mm in diameter and 60 mm in length. TPM imaging was performed by raster scanning of the excitation focus at the ...

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    9. Detection of pH-induced aggregation of "smart" gold nanoparticles with photothermal optical coherence tomography

      Detection of pH-induced aggregation of "smart" gold nanoparticles with photothermal optical coherence tomography

      We report the feasibility of a novel contrast agent, namely “smart” gold nanoparticles (AuNPs), in the detection of cancer cells with photothermal optical coherence tomography (PT-OCT). “Smart” AuNPs form aggregation in low pH condition, which is typical for cancer cells, and this aggregation results in a shift of their absorption spectrum. A PT-OCT system was developed to detect this pH-induced aggregation by combining an OCT light source and a laser with 660 nm in wavelength for photothermal excitation. Optical detection of pH-induced aggregation was tested with solution samples at two different pH conditions. An increase in optical path length (OPL ...

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    1-9 of 9
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  2. Topics in the News

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    3. (5 articles) Mathias Fink
    4. (3 articles) Ki Hean Kim
    5. (3 articles) Kate Grieve
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    7. (2 articles) Gwangju Institute of Science and Technology
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    9. (2 articles) Taejun Wang
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    16. (1 articles) Yonsei University
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    Detection of pH-induced aggregation of "smart" gold nanoparticles with photothermal optical coherence tomography Gradient index lens based combined two-photon microscopy and optical coherence tomography In vivo wide-field reflectance/fluorescence imaging and polarization-sensitive optical coherence tomography of human oral cavity with a forward-viewing probe Full-field spatially incoherent illumination interferometry: a spatial resolution almost insensitive to aberrations Adaptive optics full-field optical coherence tomography En face coherence microscopy [Invited] Retinal imaging with adaptive optics full-field OCT In vivo high resolution human corneal imaging using full-field optical coherence tomography In vivo imaging through the entire thickness of human cornea by full-field optical coherence tomography Flatly Broadened and Highly Coherent Supercontinuum Generation by Induced Modulation Instability in ANDi-PCF Impact of vessel curvature on neointimal healing after stent implantation as assessed by optical coherence tomography Optical coherence tomography angiography characterization of acute and late stage Purtscher retinopathy