1. Articles from sheng-lung huang

    1-26 of 26
    1. En Face and Cross-sectional Corneal Tomograms Using Sub-micron spatial resolution Optical Coherence Tomography

      En Face and Cross-sectional Corneal Tomograms Using Sub-micron spatial resolution Optical Coherence Tomography

      Accurate diagnosis of corneal pathology and morphological identification of different corneal layers require clear delineation of corneal three-dimensional structures and en face or cross-sectional imaging of palisade of Vogt (POV), neovascularization (NV) or corneal nerves. Here we report a prototype of full-field optical coherence tomography (FF-OCT) system with isotropic sub-micron spatial resolution in the en face and cross-sectional views. It can also provide three-dimensional reconstructed images and a large field of view (FOV) by stitching tomograms side by side. We validated the imaging power of this prototype in in vivo rat and rabbit eyes, and quantified anatomical characteristics such as ...

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    2. Feature Of The Week 08/31/2018: Spectroscopic Characterization of Si/Mo Thin-film Stack at Extreme Ultraviolet Range

      Feature Of The Week 08/31/2018: Spectroscopic Characterization of Si/Mo Thin-film Stack at Extreme Ultraviolet Range

      Using extreme ultraviolet (EUV) radiation for nanoscale imaging has recently seen much interest. As actinic patterned mask inspection tools are not available, chipmakers have to rely on wafer inspection to identify mask defects. To fulfill the requirements of mask inspection, EUV sources with high brightness, high stability (spatial and temporal), and cost effectiveness are needed. In a laser-produced-plasma (LPP) generated EUV system, a high-intensity laser beam is focused onto a tin target to form a hot plasma, which emits ultraviolet light. In this study, a fiber-laser excitation source was used to generate stable 13.5-nm EUV for spectroscopic optical coherence ...

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    3. Spectroscopic characterization of Si/Mo thin-film stack at extreme ultraviolet range

      Spectroscopic characterization of Si/Mo thin-film stack at extreme ultraviolet range

      A noninvasive method for characterizing Si/Mo thin-film stack thickness and its complex transfer function using common-path optical coherence tomography is proposed, analyzed, and experimentally demonstrated. A laser-produced plasma (LPP)-based extreme ultraviolet (EUV) source was excited by a four-stage nanosecond Yb:fiber laser amplifier with a pulse energy of 1.01 mJ. The tabletop LPP EUV source was compact and stable for generating the EUV interference fringes. The measured complex transfer function of the Si/Mo stack was verified near the pristine 13.5-nm wavelength range.

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    4. Extracting Blood Vessels From Full-Field OCT Data of Human Skin by Short-Time RPCA

      Extracting Blood Vessels From Full-Field OCT Data of Human Skin by Short-Time RPCA

      Recent advances in optical coherence tomography (OCT) lead to the development of OCT angiography to provide additional helpful information for diagnosis of diseases like basal cell carcinoma. In this paper, we investigate how to extract blood vessels of human skin from full-field OCT (FF-OCT) data using the robust principal component analysis (RPCA) technique. Specifically, we propose a short-time RPCA method that divides the FF-OCT data into segments and decomposes each segment into a low-rank structure representing the relatively static tissues of human skin and a sparse matrix representing the blood vessels. The method mitigates the problem associated with the slow-varying ...

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    5. Three-dimensional optical coherence tomography apparatus and its application

      Three-dimensional optical coherence tomography apparatus and its application

      Provided herein are devices and systems that apply full-field optical coherence tomography (OCT) technology to three-dimensional skin tissue imaging. A special designed Mirau type objective and an optical microscope module allowing both OCT mode and orthogonal polarization spectral imaging (OPSI) mode are disclosed.

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    6. Feature of The Week 03/26.2017: Segmentation of nucleus and cytoplasm of a single cell in 3D tomogram using OCT

      Feature of The Week 03/26.2017: Segmentation of nucleus and cytoplasm of a single cell in 3D tomogram using OCT

      uclear-to-cytoplasmic (N/C) ratio is an effective feature to distinguish cancer cells from their normal counterparts. In conventional cytopathology, cells printed or smeared on a glass slide were stained and then evaluated by two-dimensional (2D) images through light microscopy. A random rayburst sampling (RRBS) framework was developed to detect the nucleus and cell membrane boundaries in three-dimensional (3D) space. Raw images were acquired through a full-field optical coherence tomography (FF-OCT) system with submicron resolution—i.e. 0.8 µm in lateral and 0.9 µm in axial direction. The near isometric resolution enables 3D segmentation of nucleus and cell membrane ...

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    7. Segmentation of nucleus and cytoplasm of a single cell in three-dimensional tomogram using optical coherence tomography

      Segmentation of nucleus and cytoplasm of a single cell in three-dimensional tomogram using optical coherence tomography

      A random rayburst sampling (RRBS) framework was developed to detect the nucleus and cell membrane boundaries in three-dimensional (3-D) space. Raw images were acquired through a full-field optical coherence tomography system with submicron resolution—i.e., 0.8    μ m 0.8  μm in lateral and 0.9    μ m 0.9  μm in axial directions. The near-isometric resolution enables 3-D segmentation of a nucleus and cell membrane for determining the volumetric nuclear-to-cytoplasmic (N/C) ratio of a single cell. The RRBS framework was insensitive to the selection of seeds and image pixel noise. The robustness of the RRBS framework was verified ...

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    8. Feature Of The Week 9/28/14: National Taiwan University Reports on Full-depth epidermis tomography using a Mirau-based full-field OCT

      Feature Of The Week 9/28/14: National Taiwan University Reports on Full-depth epidermis tomography using a Mirau-based full-field OCT

      All living things are made of cells. Most living organisms are single cells; others, such as human bodies, are vast multicellular cities with an aggregation of more than 10 billion cells. Non-invasive and high speed imaging of cells and tissues with sub-micron resolution could help unveil functions of living organisms, and facilitate disease/cancer diagnosis, new drug development, etc. Such an imaging modality is one of the key technologies to detect disease and cancer in the early stage so that the ever-escalating medical cost could be controlled. At the same time, biomedical discovery often originated from technology advancement. Optical coherence ...

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    9. Full-depth epidermis tomography using a Mirau-based full-field optical coherence tomography

      Full-depth epidermis tomography using a Mirau-based full-field optical coherence tomography

      With a Gaussian-like broadband light source from high brightness Ce 3+ :YAG single-clad crystal fiber, a full-field optical coherence tomography using a home-designed Mirau objective realized high quality images of in vivo and excised skin tissues. With a 40 × silicone-oil-immersion Mirau objective, the achieved spatial resolutions in axial and lateral directions were 0.9 and 0.51 μm, respectively. Such a high spatial resolution enables the separation of lamellar structure of the full epidermis in both the cross-sectional and en face planes. The number of layers of stratum corneum and its thickness were quantitatively measured. This label free and non-invasive ...

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    10. Fabrication and Characteristics of Ce-Doped Fiber for High-Resolution OCT Source

      Fabrication and Characteristics of Ce-Doped Fiber for High-Resolution OCT Source

      The fabrication of Ce-doped fibers (CeDFs) is demonstrated by drawing-tower method employing rod-in-tube technique. The fluorescence spectrum of CeDFs with a 16-μm core exhibited a 160-nm broadband emission with 1.45-μm axial resolution. This CeDF may be functioned as a high-resolution light source for optical coherence tomography applications.

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    11. Spectroscopic measurement of absorptive thin films by Spectral-Domain Optical Coherence Tomography

      Spectroscopic measurement of absorptive thin films by Spectral-Domain Optical Coherence Tomography

      A non-invasive method for measuring the refractive index, extinction coefficient and film thickness of absorptive thin films using spectral-domain optical coherent tomography is proposed, analyzed and experimentally demonstrated. Such an optical system employing a normal-incident beam of light exhibits a high spatial resolution. There are no mechanical moving parts involved for the measurement except the transversal scanning module for the measurement at various transversal locations. The method was experimentally demonstrated on two absorptive thin-film samples coated on transparent glass substrates. The refractive index and extinction coefficient spectra from 510 to 580 nm wavelength range and film thickness were simultaneously measured ...

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    12. Apparatus for low coherence optical imaging

      Apparatus for low coherence optical imaging

      The present invention relates to an apparatus for low coherence optical imaging, and more particularly to an apparatus for low coherence optical imaging which can obtain the information of the different depths of a sample simultaneously. The apparatus comprises a phase transformation unit or a beam shift unit. The phase transformation unit or beam shift unit transforms and reflects the reference light, such that the reflected reference light comprises different phases at the different positions of a cross-section. When the reference light and a information light from the sample are superimposed on a photo detector, the information of the different ...

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    13. Three-dimensional optical coherence tomography confocal imaging apparatus

      Three-dimensional optical coherence tomography confocal imaging apparatus

      A 3D OCT confocal imaging apparatus includes a light source module for providing an illumination beam with wider bandwidth from a crystal fiber; a reference source module; a pickup module; a beam splitter; an optical filter; and a sensor module. When the illumination beam illuminates a sample, a pickup objective lens and a piezoelectric actuator of the pickup module together provide an image beam scanning the sample in depth direction. The image beam and a reference beam from the reference source module together form an interference image beam, which is converted by a photosensor into a coherence image electric signal ...

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    14. Optical imaging apparatus and method

      Optical imaging apparatus and method

      The present invention relates to an optical imaging apparatus and a method, and more particularly to an optical imaging apparatus and a method with short coherence length optical source. The apparatus comprises an optical source with a plurality of outputs for providing a reference light and a sample light; a sample probe module for leading the sample light to a sample, and leading an information light out; an interference module for leading the reference light to a photo detector, and leading the information light to the photo detector; and a signal processing unit electrically coupled to the photo detector; wherein ...

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    15. Mirau-based full-field time-domain optical coherence tomography using Ce3+ :YAG crystal fiber light source

      Mirau-based full-field time-domain optical coherence tomography using Ce3+ :YAG crystal fiber light source

      Based on single-objective construction utilizing high brightness Ce 3+ :YAG single-clad crystal fiber light source, this Mirau-based full-field time-domain optical coherence tomography with circular polarization incident light represents deeper penetration in scattering medium. Using objective-changeable ability of home-designed Mirau objective, this system provides different applications, like biological tissue and single cells, by different spatial resolution with corresponding dynamics. High quality image relying on less ghost image and near common-path interference was demonstrated under this compact and power-stable system.

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    16. Full EM wave simulation on optical coherence tomography: impact of surface roughness

      Full EM wave simulation on optical coherence tomography: impact of surface roughness

      In this paper we attempted to simulate the macroscopic light scattering phenomenon of optical coherence tomography. Numerical solutions of Maxwell’s equations were computed to accurately account for phase and amplitude of light. According to the simulation results, the qualitative and quantitative characterization may provide important information for future development of this technique, especially on the index mapping of biological cells.

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    17. Feature Of The Week 10/21/12: Cell Death Detection by Quantitative Three-Dimensional Single-Cell Tomography

      Feature Of The Week 10/21/12: Cell Death Detection by Quantitative Three-Dimensional Single-Cell Tomography


      The aim of cancer therapies is mainly to stop cell proliferation or induce cell death. Cell death regulation is important for normal development and homeostasis. Cancer cells escape from death signals and continue their abnormal proliferation. Therefore, the ability to induce death in cancer cells has been a crucial biomarker for the efficacy of chemotherapeutic agents. However, individual cancer cells, even from the same population, vary greatly in their response to cell death stimuli. Measuring the response at the single-cell levels provide further pharmacokinetic and pharmacodynamics information, which aids drug development and regimen design. Developing a microscopic technology with non-invasive ...

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    18. Cell death detection by quantitative three-dimensional single-cell tomography

      Cell death detection by quantitative three-dimensional single-cell tomography

      Ultrahigh-resolution optical coherence tomography (UR-OCT) has been used for the first time to our knowledge to study single-cell basal cell carcinoma (BCC) in vitro. This noninvasive, in situ, label-free technique with deep imaging depth enables three-dimensional analysis of scattering properties of single cells with cellular spatial resolution. From three-dimensional UR-OCT imaging, live and dead BCC cells can be easily identified based on morphological observation. We developed a novel method to automatically extract characteristic parameters of a single cell from data volume, and quantitative comparison and parametric analysis were performed. The results demonstrate the capability of UR-OCT to detect cell death ...

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    19. Diode-Laser-Pumped Glass-Clad Ti:Sapphire Crystal-Fiber-Based Broadband Light Source

      Diode-Laser-Pumped Glass-Clad Ti:Sapphire Crystal-Fiber-Based Broadband Light Source

      Glass-clad TiAlO3 crystal fibers were grown using the codrawing laser-heated pedestal growth method. Both single-clad and double-clad structures were attempted. Using a 446-nm laser diode as the pump, 2.45 mW of collimated broadband emission was generated with a 3-dB bandwidth of 180 nm. As much as 7.7 mW of output power with a 3-dB bandwidth of 182 nm was generated using a 532-nm solid-state pump laser. The broadband light source is advantageous to use in optical coherence tomography with an axial resolution of 1.5 um in air and a low image pixel crosstalk.

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    20. Near-Field Spectroscopy of Broadband Emissions from γ-Al2O3 Nanocrystals in Cr-Doped Double-Clad Fibers

      Near-Field Spectroscopy of Broadband Emissions from γ-Al2O3 Nanocrystals in Cr-Doped Double-Clad Fibers
      Embedded nanocrystals (NCs) of γ-Al2O3 in SiO2 matrixes of Cr-doped double-clad fibers (CDFs) were fabricated by the codrawing laser-heated pedestal growth technique. The spatially resolved broadband emissions of these NCs were examined as a function of NC morphology and distribution by near-field scanning optical microscopy. Comparison of the measured emissions with crystal-field ligands together with careful examination of the NC morphologies by high-resolution transmission electron microscopy confirmed this broadband emission as being an effect of nanotwinning and the Cr3+–Cr6+ redox reaction. The impact of nanotwinning on the relative strength and emission wavelength of Cr3+ and Cr6+ is potentially beneficial ...
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    21. Non-invasive characterization of the domain boundary and structure properties of periodically poled ferroelectrics

      Non-invasive characterization of the domain boundary and structure properties of periodically poled ferroelectrics
      Shaping the ferroelectric domains as waveguide, grating, lens, and prism are key to the successful penetration of periodically-poled ferroelectrics on various wavelength conversion applications. The complicated structures are, however, difficult to be fully characterized, especially the unexpected index contrast at the anti-parallel domain boundaries are typical in the order of 10−4 or less. An ultrahigh resolution optical coherence tomography was employed to fully characterize the domain boundary and structure properties of a periodically-poled lithium niobate (PPLN) waveguide with an axial resolution of 0.68 μm, an transversal resolution of 3.2 μm, and an index contrast sensitivity of 4x10 ...
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    22. Microstructural and microspectral characterization of a vertically aligned liquid crystal display panel

      Microstructural and microspectral characterization of a vertically aligned liquid crystal display panel
      e microstructural and microspectral characteristics of a vertically aligned liquid crystal display (VA-LCD) panel were obtained noninvasively for the first time. With 1 μm axial and 2 μm transversal resolutions, the cell gap profile beneath the patterned thin-film transistor of the VA-LCD panel can clearly be resolved. The thicknesses of the multiple thin-film layers and the embedded defects can also be unveiled. As far as spectral response is concerned, the light transmittance at the layer boundaries can be estimated from the measured reflectance, which is crucial information for the design of a highly transmissive panel. The color shift of the ...
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    23. Bidirectionally pumped Cr^4+:YAG crystal fiber light source for optical coherence tomography

      Bidirectionally pumped Cr^4+:YAG crystal fiber light source for optical coherence tomography
      A broadband Cr4+:YAG double-clad crystal fiber light source with a collimated output power of 3.15mW was demonstrated by using a bidirectional pump scheme. The bidirectional pump scheme increased the pumping efficiency and reduced the thermal problem along the fiber. Good agreement on the output power of the broadband fluorescence was achieved between experiment and theory, which showed a peak net gain coefficient of 0.03cm−1 at the center wavelength near 1380nm. The 3dB bandwidth of 222nm with a Gaussian-like spectrum makes it eminently suitable for broadband interferometric technique to have low image cross talk. The calculated interference ...
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    24. High-Luminance White-Light Point Source Using Ce,Sm : YAG Double-Clad Crystal Fiber

      High-Luminance White-Light Point Source Using Ce,Sm : YAG Double-Clad Crystal Fiber
      Ce and Sm ions codoped yttrium aluminum garnet (Ce,Sm : YAG) double-clad crystal fibers (DCFs) were successfully fabricated using the codrawing laser-heated pedestal growth method. At a pump wavelength of 446 nm, white-light point source was produced from a 10-$mu{hbox {m}}$-core DCF. The amplified spontaneous emissions and the residual pump resulted in a directional high brightness point source. A luminance of $4.5times 10 ^{9}~hbox{cd}/hbox{m} ^{2}$ was generated. The luminous flux of the point white light was 6.2 lm. When coupled to a 200-$mu{hbox {m}}$-core multimode fiber, the output ...
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    25. Ce^3+:YAG double-clad crystal-fiber-based optical coherence tomography on fish cornea

      Ce^3+:YAG double-clad crystal-fiber-based optical coherence tomography on fish cornea
      A Ce3+:YAG double-clad crystal fiber (DCF) visible emission was used as the light source for optical coherence tomography (OCT). The visible emission was produced from a 10 μm core DCF pumped by a diode laser. The broadband emission and short central wavelength of this light source enabled the realization of 1.5 μm axial resolution in air. The relatively clean spectrum reduced the side lobe of its point-spread function, and therefore facilitated the generation of a high-quality image with less crosstalk between adjacent image pixels. As a demonstration, an Aplocheilus lineatus goldfish was experimented on to map out the ...
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    26. High speed interferometric ellipsometer

      A novel high speed interferometric ellipsometer (HSIE) is proposed and demonstrated. It is based on a novel differential-phase decoder which is able to convert the phase modulation into amplitude modulation in a polarized heterodyne interferometer. Not only high detection sensitivity but also fast ... [Opt. Express 16, 7778-7788 (2008)]
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    1-26 of 26
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    1. (26 articles) National Taiwan University
    2. (26 articles) Sheng-Lung Huang
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    Ce^3+:YAG double-clad crystal-fiber-based optical coherence tomography on fish cornea High-Luminance White-Light Point Source Using Ce,Sm : YAG Double-Clad Crystal Fiber Bidirectionally pumped Cr^4+:YAG crystal fiber light source for optical coherence tomography Microstructural and microspectral characterization of a vertically aligned liquid crystal display panel Non-invasive characterization of the domain boundary and structure properties of periodically poled ferroelectrics Near-Field Spectroscopy of Broadband Emissions from γ-Al2O3 Nanocrystals in Cr-Doped Double-Clad Fibers Diode-Laser-Pumped Glass-Clad Ti:Sapphire Crystal-Fiber-Based Broadband Light Source Feature Of The Week 10/21/12: Cell Death Detection by Quantitative Three-Dimensional Single-Cell Tomography Feature of The Week 03/26.2017: Segmentation of nucleus and cytoplasm of a single cell in 3D tomogram using OCT Optical coherence tomography features of neovascularization in proliferative diabetic retinopathy: a systematic review Retinal microvascular metrics in untreated essential hypertensives using optical coherence tomography angiography Optical coherence tomography angiography findings of fellow eye of proliferative macular telangiectasia type 2: Long term study