1. Articles from Daniel L. Marks

    1-21 of 21
    1. Diffusion tensor optical coherence tomography

      Diffusion tensor optical coherence tomography

      In situ measurements of diffusive particle transport provide insight into tissue architecture, drug delivery, and cellular function. Analogous to diffusion-tensor magnetic resonance imaging (DT-MRI), where the anisotropic diffusion of water molecules is mapped on the millimeter scale to elucidate the fibrous structure of tissue, here we propose diffusion-tensor optical coherence tomography (DT-OCT) for measuring directional diffusivity and flow of optically scattering particles within tissue. Because DT-OCT is sensitive to the sub-resolution motion of Brownian particles as they are constrained by tissue macromolecules, it has the potential to quantify nanoporous anisotropic tissue structure at micrometer resolution as relevant to extracellular matrices ...

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    2. Inverse scattering for frequency-scanned full-field optical coherence tomography

      Inverse scattering for frequency-scanned full-field optical coherence tomography

      Full-field optical coherence tomography (OCT) is able to image an entire en face plane of scatterers simultaneously, but typically the focus is scanned through the volume to acquire three-dimensional structure. By solving the inverse scattering problem for full-field OCT, we show it is possible to computationally reconstruct a three-dimensional volume while the focus is fixed at one plane inside the sample. While a low-numerical-aperture (NA) OCT system can tolerate defocus because the depth of field is large, for high NA it is critical to correct for defocus. By deriving a solution to the inverse scattering problem for full-field OCT, we ...

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    3. Group refractive index reconstruction with broadband interferometric confocal microscopy

      Group refractive index reconstruction with broadband interferometric confocal microscopy

      A system and method for microscale measurement and imaging of the group refractive index of a sample. The method utilizes a broadband confocal high-numerical aperture microscope embedded into an interferometer and a spectrometric means, whereby spectral interferograms are analyzed to compute optical path delay of the beam traversing the sample as the sample is translated through the focus of an interrogating light beam. A determination of group refractive index may serve to disambiguate phase ambiguity in a measurement of refractive index at a specified wavelength. Spatial resolution of object characterization in three dimensions is achieved by imaging the object from ...

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    4. Spatial light interference tomography (SLIT)

      Spatial light interference tomography (SLIT)
      We present spatial light interference tomography (SLIT), a label-free method for 3D imaging of transparent structures such as live cells. SLIT uses the principle of interferometric imaging with broadband fields and combines the optical gating due to the micron-scale coherence length with that of the high numerical aperture objective lens. Measuring the phase shift map associated with the object as it is translated through focus provides full information about the 3D distribution associated with the refractive index. Using a reconstruction algorithm based on the Born approximation, we show that the sample structure may be recovered via a 3D, complex field ...
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    5. Molecular Histopathology by Spectrally Reconstructed Nonlinear Interferometric Vibrational Imaging

      Molecular Histopathology by Spectrally Reconstructed Nonlinear Interferometric Vibrational Imaging
      Sensitive assays for rapid quantitative analysis of histologic sections, resected tissue specimens, or in situ tissue are highly desired for early disease diagnosis. Stained histopathology is the gold standard but remains a subjective practice on processed tissue taking from hours to days. We describe a microscopy technique that obtains a sensitive and accurate color-coded image from intrinsic molecular markers. Spectrally reconstructed nonlinear interferometric vibrational imaging can differentiate cancer versus normal tissue sections with greater than 99% confidence interval in a preclinical rat breast cancer model and define cancer boundaries to ±100 μm with greater than 99% confidence interval, using fresh ...
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    6. Cross-validation of interferometric synthetic aperture microscopy and optical coherence tomography

      Cross-validation of interferometric synthetic aperture microscopy and optical coherence tomography
      Computationally reconstructed interferometric synthetic aperture microscopy is coregistered with optical coherence tomography (OCT) focal plane data to provide quantitative cross validation with OCT. This is accomplished through a qualitative comparison of images and a quantitative analysis of the width of the point-spread function in simulation and experiment. The width of the ISAM point-spread function is seen to be independent of depth, in contrast to OCT.
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    7. Partially coherent illumination for inverse scattering full-field interferometric synthetic aperture microscopy

      Methods and apparatus for three-dimensional imaging of a sample. A source is provided of a beam of light characterized by partial spatial coherence. The beam is focused onto a sample and scattered light from the sample is superposed with a reference beam derived from the source onto a focal plane detector array to provide an interference signal. A forward scattering model is derived relating measurement data to structure of an object to allow solutions of an inverse scattering problem, based upon the interference signal so that a three-dimensional structure of the same may be inferred. The partial spatial coherence of ...
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    8. Nonlinear interferometric vibrational imaging

      A method of examining a sample, which includes: exposing a reference to a first set of electromagnetic radiation, to form a second set of electromagnetic radiation scattered from the reference; exposing a sample to a third set of electromagnetic radiation to form a fourth set of electromagnetic radiation scattered from the sample; and interfering the second set of electromagnetic radiation and the fourth set of electromagnetic radiation. The first set and the third set of electromagnetic radiation are generated from a source; at least a portion of the second set of electromagnetic radiation is of a frequency different from that ...
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    9. Interferometric synthetic aperture microscopy

      Methods and apparatus for three-dimensional imaging of a sample. A source is provided of a beam of substantially collimated light characterized by a temporally dependent spectrum. The beam is focused in a plane characterized by a fixed displacement along the propagation axis of the beam, and scattered light from the sample is superposed with a reference beam derived from the substantially collimated source onto a focal plane detector array to provide an interference signal. A forward scattering model is derived relating measured data to structure of an object to allow solution of an inverse scattering problem based upon the interference ...
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    10. Validation of nonlinear interferometric vibrational imaging as a molecular OCT technique by the use of Raman microscopy

      We validate a molecular imaging technique called Nonlinear Interferometric Vibrational Imaging (NIVI) by comparing vibrational spectra with those acquired from Raman microscopy. This broadband coherent anti-Stokes Raman scattering (CARS) technique uses heterodyne detection and OCT acquisition and design principles to interfere a CARS signal generated by a sample with a local oscillator signal generated separately by a four-wave mixing process. These are mixed and demodulated by spectral interferometry. Its confocal configuration allows the acquisition of 3D images based on endogenous molecular signatures. Images from both phantom and mammary tissues have been acquired by this instrument and its spectrum is compared ...
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    11. Partially coherent illumination in full-field interferometric synthetic aperture microscopy

      A model is developed for optical coherence tomography and interferometric synthetic aperture microscopy (ISAM) systems employing full-field frequency-scanned illumination with partial spatial coherence. This model is used to derive efficient ISAM inverse scattering algorithms that give ... [J. Opt. Soc. Am. A 26, 376-386 (2009)]
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    12. Interferometric Synthetic Aperture Microscopy: Physics-Based Image Reconstruction from Optical Coherence Tomography Data

      Optical coherence tomography (OCT) is an optical ranging technique analogous to radar - detection of back-scattered light produces a signal that is temporally localized at times-of-flight corresponding to the location of scatterers in the object. However the interferometric collection technique used in OCT allows, in principle, the coherent collection of data, i.e. amplitude and phase information can be extracted. Interferometric synthetic aperture microscopy (ISAM) adds phase-stable data collection to OCT instrumentation and employs physics-based processing analogous to that used in synthetic aperture radar (SAR). That is, the complex nature of the coherent data is exploited to give gains in image ...
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    13. Volumetric endoscopic coherence microscopy using a coherent fiber bundle

      Methods for employing coherent bundles of optical fibers, whether single- or multi-mode, for optical coherence tomography or optical coherence microscopy. Either a substantially monochromatic source or a broadband source is spatially decohered and/or spatially filtered prior to coupling into the fiber bundle for illumination of a sample. A scatter signal from features disposed beneath the surface of the sample is interfered with a reference signal derived, at either end of the fiber bundle, from the identical source of illumination.
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    14. Plastinated tissue samples as three-dimensional models for optical instrument characterization

      Daniel L. Marks, Eric J. Chaney, Stephen A. Boppart Histology of biological specimens is largely limited to investigating two-dimensional structure because of the sectioning required to produce optically thin samples for conventional microscopy. With the advent of three-dimensional optical imaging technologies such as optical coherence tomography ... [Opt. Express 16, 16272-16283 (2008)]
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    15. High-speed processing architecture for spectral-domain optical coherence microscopy

      Robin G. Chelliyil, Tyler S. Ralston, Daniel L. Marks et al. Optical coherence microscopy (OCM) is an interferometric technique that combines principles of confocal microscopy and optical coherence tomography (OCT) to obtain high-resolution en face images. Axial and lateral resolutions of several microns can be achieved using OCM depending on the numerical ap ... [J. Biomed. Opt. 13, 044013 (2008)] published Fri Aug 8, 2008.
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    16. Volumetric Endoscopic Coherence Microscopy Using A Coherent Fiber Bundle (Wo 2008/091755)

      Volumetric Endoscopic Coherence Microscopy Using A Coherent Fiber Bundle (Wo 2008/091755)
      Methods for employing coherent bundles of optical fibers, whether single- or multi-mode, for optical coherence tomography or optical coherence microscopy. Either a substantially monochromatic source or a broadband source (200) has its spatial coherence reduced and/or is spatially filtered prior to coupling into the fiber bundle for 'illumination of a sample. A scattered signal from features disposed beneath the surface of the sample is interfered with a reference signal derived, at either end of the fiber bundle, from the identical source of illumination.
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    17. Stabilization of continuum generation from normally dispersive nonlinear optical fibers for a tunable broad bandwidth source for optical coherence tomography

      Haohua Tu, Daniel L. Marks, Yee Lin Koh, and Stephen A. Boppart Continuum generation from normally dispersive ultrahigh-numerical-aperture fibers deteriorates in relatively short times, limiting its application as a practical optical source for high-resolution optical coherence tomography. We find that reversible light-induced structural modification of fiber optic materials, rather than permanent optical damage, is responsible for this deterioration. By examining how the optical properties of corresponding light-induced waveguides depend on pumping wavelength, we isolate a waveguide that is beneficial for stable continuum generation. The performance deterioration due to the formation of other waveguides can be reversed by overwriting them with ...
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    18. Interferometric synthetic aperture microscopy: tissue structure inferred by computed imaging techniques

      Interferometric synthetic aperture microscopy: tissue structure inferred by computed imaging techniques
      Daniel L. Marks, Tyler S. Ralston, Brynmor J. Davis et al. Interferometric Synthetic Aperture Microscopy (ISAM) is an optical microscopy computed-imaging technique for measuring the optical properties of three-dimensional structures and biological tissues. In this work, the principle of ISAM is reviewed, and its application to imaging tissue properties in v ... [Proc. SPIE Int. Soc. Opt. Eng. 6864, 686407 (2008)] published Fri Feb 15, 2008.
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    19. Real-time interferometric synthetic aperture microscopy

      Tyler S. Ralston, Daniel L. Marks, P. S. Carney, Stephen A. Boppart. An interferometric synthetic aperture microscopy (ISAM) system design with real-time 2D cross-sectional processing is described in detail. The system can acquire, process, and display the ISAM reconstructed images at frame rates of 2.25 frames per second for 512 X 1024 pixel images. This system ... [Opt. Express 16, 2555-2569 (2008)]
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    20. Optical contrast agents for optically modifying incident radiation

      A method of enhancing the contrast of an image of a sample, comprises forming an image of a mixture, by exposing the mixture to electromagnetic radiation. The mixture comprises the sample and microparticles. The enhancement is particularly suitable for optical coherence tomography.

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    21. Interferometric synthetic aperture microscopy

      Interferometric synthetic aperture microscopy
      State-of-the-art methods in high-resolution three-dimensional optical microscopy require that the focus be scanned through the entire region of interest. However, an analysis of the physics of the light–sample interaction reveals that the Fourier-space coverage is independent of depth. Here we show that, by solving the inverse scattering problem for interference microscopy, computed reconstruction yields volumes with a resolution in all planes that is equivalent to the resolution achieved only at the focal plane for conventional high-resolution microscopy. In short, the entire illuminated volume has spatially invariant resolution, thus eliminating the compromise between resolution and depth of field. We describe ...
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    1-21 of 21
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    1. (21 articles) Daniel L. Marks
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    Interferometric synthetic aperture microscopy: tissue structure inferred by computed imaging techniques Volumetric Endoscopic Coherence Microscopy Using A Coherent Fiber Bundle (Wo 2008/091755) Cross-validation of interferometric synthetic aperture microscopy and optical coherence tomography Molecular Histopathology by Spectrally Reconstructed Nonlinear Interferometric Vibrational Imaging Notal Vision Engages Wasatch Photonics Bringing AI-Enabled Home-Based Optical Coherence Tomography Closer to Market Semiconductor Lasers and Diode-based Light Sources for Biophotonics (Textbook) Inside the “Razor Effect”: Lessons From Optical Coherence Tomography—What Does Angiography Hide? Imaging the Human Prostate Gland Using 1-μm-Resolution Optical Coherence Tomography In Vivo and Ex Vivo Microscopy: Moving Toward the Integration of Optical Imaging Technologies Into Pathology Practice Recognition of calcified neoatherosclerosis Spectral domain optical coherence tomography as an adjunctive tool for screening Behçet uveitis Thickness of the Macula, Retinal Nerve Fiber Layer, and Ganglion Cell-inner Plexiform Layer in the Macular Hole: The Repeatability Study of Spectral-domain Optical Coherence Tomography