1. Articles from Jihoon Na

    1-15 of 15
    1. Tomographic imaging of incipient dental-caries using optical coherence tomography and comparison with various modalities

      We present the optical coherence tomography (OCT) made to investigate the early dental caries in human teeth and compare its results with those taken by conventional imaging modalities including light illuminating examination (LIE), digital intra-oral radiography (DIOR), and electron probe micro analyzer (EPMA). Morphological features and caries-involved areas of the dental structure were mainly investigated by LIE, DIOR, and OCT to study the infection of the caries lesion in pits and fissures. The biochemical information acquired with EPMA and the morphological features taken with OCT in the early stage of caries were compared and analyzed to present an objective and ...
      Read Full Article
    2. Single-body lensed-fiber scanning probe actuated by magnetic force for optical imaging

      Single-body lensed-fiber scanning probe actuated by magnetic force for optical imaging
      We propose a fiber-based hand-held scanning probe suitable for the sample arm of an optical imaging system including optical coherence tomography. To achieve compactness, a single-body lensed-fiber and a solenoid actuator were utilized. The focusing lens of the probe was directly formed onto the distal end of a fiber, which eliminated the need for additional optical components and optical alignment. A ferromagnetic iron bead was glued onto the middle of the fiber to enable actuation by magnetic force, which allowed easy fabrication and good practicality. The fiber piece having the built-in fiber lens was forced to oscillate in its resonant ...
      Read Full Article
    3. Thickness and index measurements of a transparent specimen by full-field optical coherence microscopy

      We present the method measuring the thickness and the refractive index of a transparent specimen at a same time based on full-field optical coherence tomography. As a sample a small drop of epoxy was placed on a flat plate and the high-resolution depth resolved en-face images of the epoxy drop were taken. With adopting the plate surface as a reference plane, the physical thickness and the refractive index distribution could be obtained. Owing to the full-field imaging capability, we could obtain the transverse distributions of the thickness and the refractive index without any transverse scanning. The measured thickness at the ...
      Read Full Article
    4. Stroboscopic wide-field optical coherence gated imaging

      We present an advanced three-dimensional tomographic imaging system using the optical coherence gating based on stroboscopic illumination. The proposed system is based on a wide-field optical coherence tomography (WF-OCT) that is capable of en-face tomographic imaging through whole-field illumination and parallel detection technique. The scheme enables achievement of a three-dimensional volumetric image in real time only with a single axial continuous scanning. The axial scanning of the OCT system generates interferometric signal with a beat (or Doppler) frequency. The time-varying interfergams are usually detected in series with a CCD camera for the WF-OCT case. However, because the camera response is ...
      Read Full Article
    5. Simultaneous measurements of optical coherence tomography and fluorescence spectroscopy based on double clad fiber

      We report an all-fiber system aided by double-clad fiber (DCF) and DCF devices for simultaneous measurements of optical coherence tomography (OCT) and fluorescence spectroscopy (FS). The DCF together with DCF coupler and single-body DCF lens helped in realizing a ultifunctional single-unit probe fo ... [Proc. SPIE 7171, 71710T (2009)] published Fri Feb 20, 2009.
      Read Full Article
    6. Single-body lensed fiber probe actuated by magnetic force for spectral domain optical coherence tomography

      We propose a fiber-based hand-held scanning probe suitable for the sample arm of spectral domain optical coherence tomography (SD-OCT). To achieve a compact and miniaturized probe, a single-body lensed-fiber, on which an iron-bead ferromagnetic material is loaded was fabricated and a solenoid actuat ... [Proc. SPIE 7168, 71682I (2009)] published Fri Feb 20, 2009.
      Read Full Article
    7. Optical approach to the periodontal ligament under orthodontic tooth movement: A preliminary study with optical coherence tomography

      Optical approach to the periodontal ligament under orthodontic tooth movement: A preliminary study with optical coherence tomography
      Introduction: Optical coherence tomography (OCT) is a diagnostic tool that can make near-histologic tomographic images without a biohazard. Due to its high resolution (average, 4 μm) and safety (using light as the source), it has been applied widely in medical fields to replace invasive biopsies. But the trials in dentistry have been restricted to mainly detecting dental caries and oral cancer. In this preliminary study for successive human studies, we tried to evaluate whether OCT can be helpful in determining tooth movement under light orthodontic forces. Methods: Orthodontic distraction forces (0, 5, and 10 g) were applied to the mandibular ...
      Read Full Article
    8. Combined system of optical coherence tomography and fluorescence spectroscopy based on double-cladding fiber

      We report the development of an all-fiber multimodal system, based on a double-cladding fiber (DCF) and related devices, suitable for simultaneous measurements of optical coherence tomography (OCT) and fluorescence spectroscopy (FS). The DCF together with a DCF coupler and a single-body DCF lens ... [Opt. Lett. 33, 2347-2349 (2008)]
      Read Full Article
    9. Simultaneous measurement of refractive index and thickness by combining low-coherence interferometry and confocal optics

      We propose and demonstrate novel methods that enable simultaneous measurements of the phase index, the group index, and the geometrical thickness of an optically transparent object by combining optical low-coherence interferometer and confocal optics. The low-coherence interferometer gives ... [Opt. Express 16, 5516-5526 (2008)]
      Read Full Article
    10. Lensed fiber probes designed as an alternative to bulk probes in optical coherence tomography

      We demonstrate a compact all-fiber sampling probe for an optical coherence tomography (OCT) system. By forming a focusing lens directly on the tip of an optical fiber, a compact sampling probe could be implemented. To simultaneously achieve a sufficiently long working distance and a good lateral ... [Appl. Opt. 47, 1510-1516 (2008)]
      Read Full Article
    11. All-fiber probe for optical coherence tomography

      Seon Young Ryu, Hae Young Choi, Jihoon Na et al. We propose an all-fiber probe for the sample arm of an optical coherence tomography (OCT) system. By forming a focusing lens directly on the tip of an optical fiber, a compact sample probe could be implemented. To achieve a long enough working distance and a high enough lateral resolution at the sam ... [Proc. SPIE Int. Soc. Opt. Eng. 6847, 68472L (2008)] published Mon Feb 18, 2008.
      Read Full Article
    12. Optical approach for monitoring the periodontal ligament changes induced by orthodontic forces around maxillary anterior teeth of white rats

      Optical approach for monitoring the periodontal ligament changes induced by orthodontic forces around maxillary anterior teeth of white rats
      Abstract  Structural variations of the periodontal ligament (PDL) induced by orthodontic forces have been evaluated by optical coherence tomography (OCT) and compared to images obtained by conventional radiography. Here, two specially designed orthodontic appliances were installed on the maxillary anterior teeth of white rats for applying different magnitudes of orthodontic forces. Constant distraction force magnitudes of 0, 5, 10, and 30 gf were given to four respective rats over a period of 5 days. At the end of the treatment period, the rats were sacrificed and the maxillaries were extracted for X-ray and OCT imaging. The PDL variations, proportional to ...
      Read Full Article
    13. Image restoration method based on Hilbert transform for full-field optical coherence tomography

      A full-field optical coherence tomography (FF-OCT) system utilizing a simple but novel image restoration method suitable for a high-speed system is demonstrated. An en-face image is retrieved from only two phase-shifted interference fringe images through using the mathematical Hilbert transform. ... [Appl. Opt. 47, 459-466 (2008)]
      Read Full Article
    14. Single-body lensed photonic crystal fibers as side-viewing probes for optical imaging systems.

      We report the fabrication and performance of a lensed photonic crystal fiber (PCF) designed as a compact but effective side-viewing optical imaging probe. The lensed-PCF probe was implemented in a single body without using any other fibers or additional optics. The beam expansion region and a focusing ball lens, necessary for a focuser, were simultaneously formed along a small piece of PCF by applying arc discharges. The side-viewing ability was provided by polishing the ball lens with a femtosecond laser to form a total internal reflection surface. The working distance and the transverse resolution of the fabricated single-body lensed-PCF were ...
      Read Full Article
    15. Single-body lensed photonic crystal fibers as side-viewing probes for optical imaging systems

      We report the fabrication and performance of a lensed photonic crystal fiber (PCF) designed as a compact but effective side-viewing optical imaging probe. The lensed-PCF probe was implemented in a single body without using any other fibers or additional optics. The beam expansion region and a ... [Opt. Lett. 33, 34-36 (2008)]
      Read Full Article
    1-15 of 15
  1. Categories

    1. Applications:

      Art, Cardiology, Dentistry, Dermatology, Developmental Biology, Gastroenterology, Gynecology, Microscopy, NDE/NDT, Neurology, Oncology, Ophthalmology, Other Non-Medical, Otolaryngology, Pulmonology, Urology
    2. Business News:

      Acquisition, Clinical Trials, Funding, Other Business News, Partnership, Patents
    3. Technology:

      Broadband Sources, Probes, Tunable Sources
    4. Miscellaneous:

      Jobs & Studentships, Student Theses, Textbooks
  2. Topics in the News

    1. (15 articles) Gwangju Institute of Science and Technology
    2. (15 articles) Jihoon Na
    3. (14 articles) Byeong Ha Lee
    4. (11 articles) Seon Young Ryu
    5. (7 articles) Hae Young Choi
    6. (5 articles) Woo June Choi
    7. (2 articles) University of Ulsan
    8. (2 articles) Eun Jung Min
    9. (1 articles) Jonghyun Eom
    10. (1 articles) Sun Yat-Sen University
    11. (1 articles) National Institutes of Health
    12. (1 articles) University of Illinois at Urbana-Champaign
    13. (1 articles) Tianjin University
    14. (1 articles) Zhejiang University
    15. (1 articles) New York Eye and Ear Infirmary
    16. (1 articles) Eric J. Chaney
    17. (1 articles) Jun Zhang
    18. (1 articles) Robert Ritch
    19. (1 articles) Stephen A. Boppart
  3. Popular Articles

  4. Picture Gallery

    Optical approach for monitoring the periodontal ligament changes induced by orthodontic forces around maxillary anterior teeth of white rats Optical coherence tomography angiography in glaucoma Handheld optical coherence tomography for clinical assessment of dental plaque and gingiva Characterisation of macular superficial vessel density alteration in preclinical ethambutol-induced optic neuropathy using optical coherence tomography angiography Three-dimensional spatial reconstruction of coronary arteries based on fusion of intravascular optical coherence tomography and coronary angiography Dynamic-range compression and contrast enhancement in swept-source optical coherence tomography systems with a frequency gain compensation amplifier Healing and early stent coverage after ultrathin strut biodegradable polymer-coated sirolimus-eluting stent implantation: SiBi optical coherence tomography study Optical coherence tomography angiography of choroidal neovascularization in immune choroiditis following acute retinal necrosis Operation Night Watch: getting closer to Rembrandt despite distancing Anatomical and functional healing after resorbable magnesium scaffold implantation in human coronary vessels: A combined optical coherence tomography and quantitative flow ratio analysis "Predicting Glaucoma Progression With Optical Coherence Tomography Structural and Angiographic Parameters". Intravascular Imaging-Guided Percutaneous Coronary Intervention: A Universal Approach for Optimization of Stent Implantation