1. Articles from Michael Ponting

    1-4 of 4
    1. Volumetric rendering and metrology of spherical gradient refractive index lens imaged by angular scan optical coherence tomography system

      Volumetric rendering and metrology of spherical gradient refractive index lens imaged by angular scan optical coherence tomography system

      In this paper, we develop the methodology, including the refraction correction, geometrical thickness correction, coordinate transformation, and layer segmentation algorithms, for 3D rendering and metrology of a layered spherical gradient refractive index (S-GRIN) lens based on the imaging data collected by an angular scan optical coherence tomography (OCT) system. The 3D mapping and rendering enables direct 3D visualization and internal defect inspection of the lens. The metrology provides assessment of the surface geometry, the lens thickness, the radii of curvature of the internal layer interfaces, and the misalignment of the internal S-GRIN distribution with respect to the lens surface. The ...

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    2. Simultaneous estimation of thickness and refractive index of layered gradient refractive index optics using a hybrid confocal-scan swept-source optical coherence tomography system

      Simultaneous estimation of thickness and refractive index of layered gradient refractive index optics using a hybrid confocal-scan swept-source optical coherence tomography system

      A hybrid confocal-scan swept-source optical coherence tomography metrology system was conceived for simultaneous measurements of the refractive index and thickness profiles of polymeric layered gradient refractive index (GRIN) optics. An uncertainty analysis predicts the metrology capability of the system and guides the selection of an optimum working numerical aperture. Experimental results on both a monolithic and a GRIN layered sheet are demonstrated to be in close agreement with theoretical predictions. Index measurement precision reached 0.0001 and 0.0008 for measuring 2.8 mm and ~300 µm thick layers, respectively. The thicknesses of these layers were simultaneously measured with a ...

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    3. Angular scan optical coherence tomography imaging and metrology of spherical gradient refractive index preforms

      Angular scan optical coherence tomography imaging and metrology of spherical gradient refractive index preforms

      The fabrication of high-performance spherical gradient refractive index (S-GRIN) optics requires nondestructive metrology techniques to inspect the samples. We have developed an angular-scan, swept-source-based, Fourier-domain optical coherence tomography system centered at 1318 nm with 5 mm imaging depth capable of 180̊ polar scan and 360̊ azimuthal scan to investigate polymeric S-GRIN preforms. We demonstrate a method that enables simultaneous mapping of the group optical thickness, physical thickness, the radially-averaged group refractive index, and the transmitted wavefront of the S-GRIN preforms. The angular scan OCT imaging and metrology enables direct visualization, molding uniformity characterization, and optical property evaluations of the preforms ...

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    4. Optical Coherence Tomography Enabling Non Destructive Metrology of Layered Polymeric GRIN Material

      Optical Coherence Tomography Enabling Non Destructive Metrology of Layered Polymeric GRIN Material

      Gradient Refractive INdex (GRIN) optical components have historically fallen short of theoretical expectations. A recent breakthrough is the manufacturing of nanolayered spherical GRIN (S-GRIN) polymer optical elements, where the construction method yields refractive index gradients that exceed 0.08. Here we report on the application of optical coherence tomography (OCT), including micron-class axial and lateral resolution advances, as effective, innovative methods for performing nondestructive diagnostic metrology on S-GRIN. We show that OCT can be used to visualize and quantify characteristics of the material throughout the manufacturing process. Specifically, internal film structure may be revealed and data are processed to extract ...

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    1-4 of 4
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  2. Topics in the News

    1. (4 articles) University of Rochester
    2. (4 articles) Jannick P. Rolland
    3. (3 articles) Panomsak Meemon
    4. (2 articles) Kevin P. Thompson
    5. (1 articles) Kye-Sung Lee
    6. (1 articles) University of Minnesota
    7. (1 articles) Tsinghua University
    8. (1 articles) University of Milan
    9. (1 articles) Università Vita-Salute San Raffaele
    10. (1 articles) Columbia University
    11. (1 articles) Hanyang University
    12. (1 articles) Donald C. Hood
    13. (1 articles) Taner Akkin
    14. (1 articles) Wei Chang
    15. (1 articles) Giovanni Staurenghi
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    Optical Coherence Tomography Enabling Non Destructive Metrology of Layered Polymeric GRIN Material Angular scan optical coherence tomography imaging and metrology of spherical gradient refractive index preforms Simultaneous estimation of thickness and refractive index of layered gradient refractive index optics using a hybrid confocal-scan swept-source optical coherence tomography system Volumetric rendering and metrology of spherical gradient refractive index lens imaged by angular scan optical coherence tomography system IMAGING TECHNIQUE FROM BECKMAN LAB NAMED TOP 10 MICROSCOPY INNOVATION Optical coherence refraction tomography University of Southern California Receives NIH Grant for Imaging Cerebral and Retinal Microvasculature in Cerebral Small Vessel Disease Columbia University Receives NIH Grant  for Measures of Human Receptor and post Receptor Activity Multimodal Imaging of Multiple Evanescent White Dot Syndrome: A New Interpretation MULTIMODAL IMAGING AND TREATMENT OF SYPHILITIC CHOROIDAL NEOVASCULARIZATION Highly coherent supercontinuum generation in CS2 infiltrated single-core optical fiber Glioma cell migration dynamics in brain tissue assessed by multimodal optical imaging