1. Articles from Kwan Seob Park

    1-10 of 10
    1. Angiographic Imaging of an In Vivo Mouse Brain as a Guiding Star for Automatic Digital Refocusing in OCT

      Angiographic Imaging of an In Vivo Mouse Brain as a Guiding Star for Automatic Digital Refocusing in OCT

      A method allows the extraction of the recovery factor that maximizes the image contrast of OCT (optical coherence tomography) and/or OCTA (OCT angiography) of a living subject is proposed in this study. Due to the finite depth of focus in imaging optics, the volume OCT imaging suffers from blurriness in the lateral resolution. By utilizing the digital hologram method or angular spectrum method, the blurred image can be refocused. However, for in vivo OCT imaging, evaluation of the image focus is not easy, owing to the cloudy structure of the brain. In the proposed method, the blood flow signals ...

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    2. Buffered polarization diverse detection for single-camera polarization-sensitive optical coherence tomography

      Buffered polarization diverse detection for single-camera polarization-sensitive optical coherence tomography

      Herein we propose a method to mitigate a position mismatch problem for a spectral-domain polarization-sensitive optical coherence tomography (SD-PS-OCT) system that uses a single line-scan detection scheme. A single detector-based PS-OCT detects two orthogonal polarization components as two adjacent A-scan signals in turns. Thus, two adjacent A-scan signals are not scattered at a fixed point in time (position mismatch problem), resulting in uncorrelated signals between them. To achieve sequential detection of simultaneously scattered light, a buffering single-mode fiber was connected to one of the two ports coming out of the optical switch, provided a proper time delay. A single-mode optical ...

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    3. Deep brain optical coherence tomography angiography in mice: in vivo, noninvasive imaging of hippocampal formation

      Deep brain optical coherence tomography angiography in mice: in vivo, noninvasive imaging of hippocampal formation

      The hippocampus is associated with memory and navigation, and the rodent hippocampus provides a useful model system for studying neurophysiology such as neural plasticity. Vascular changes at this site are closely related to brain diseases, such as Alzheimer’s disease, dementia, and epilepsy. Vascular imaging around the hippocampus in mice may help to further elucidate the mechanisms underlying these diseases. Optical coherence tomography angiography (OCTA) is an emerging technology that can provide label-free blood flow information. As the hippocampus is a deep structure in the mouse brain, direct in vivo visualisation of the vascular network using OCTA and other microscopic ...

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    4. Real-time stroboscopic full-field optical coherence tomography based on graphics processing unit

      Real-time stroboscopic full-field optical coherence tomography based on graphics processing unit

      We present the real-time stroboscopic full-field optical coherence tomography (FF-OCT) system that is based on graphics processing unit (GPU). The basic configuration of the proposed FF-OCT system was the Linnik interferometer. While scanning of a reference mirror in the axial direction, a series of the transverse sectional image was captured with a 2-dimensional CCD camera. To get a depth-resolved 3-D image, the light source of OCT was turned on and off like a stroboscope at the Doppler frequency of the OCT system. The CCD camera used in experiment operated at a rate of 200 frames per second, but the Doppler ...

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    5. Single-camera polarization-sensitive full-field optical coherence tomography with polarization switch

      Single-camera polarization-sensitive full-field optical coherence tomography with polarization switch

      We present a single-channel detection-based polarization-sensitive full-field optical coherence tomography (PS-FF-OCT) for simultaneous acquisition of high-resolution OCT and linear retardance images. A linearly polarized sub-10-fs laser was used as a broadband light source for the OCT system. A bi-stable polarization switching device, composed of a ferroelectric liquid crystal cell and an analyzer, was employed to get the horizontal and the vertical polarization components of a full-field interference signal. The time-switched two perpendicular interference signals were sequentially recorded by a single charge-coupled device camera, then processed to extract en-face functional images of a biological sample. The rat tail tendon was imaged ...

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    6. Polarization sensitive full-field optical coherence tomography based on bi-stable polarizaton switch

      Polarization sensitive full-field optical coherence tomography based on bi-stable polarizaton switch

      We present polarization-sensitive full-field optical coherence tomography (PS-FF-OCT), which is based on a bi-stable polarization switch (BSPS) device. The proposed PS-FF-OCT is a Linnik type interferometer, and allows getting both the birefringence-induced phase retardation and the intensity images of specimens with high resolutions using a pair of micro objectives and a BSPS device. Two orthogonal polarization states are formed with a regular time interval by the BSPS device that changes the polarization direction of light in a short time by switching its optic axes. Therefore, both the horizontally polarized light signal and the vertically polarized light signal from the sample ...

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    7. Feature Of The Week 8/26/12: Gwangju Institute of Science and Technology Investigate Tomography Imaging of Single Living Cell Using Optical Tweezers and FF-OCT

      Feature Of The Week 8/26/12: Gwangju Institute of Science and Technology Investigate Tomography Imaging of Single Living Cell Using Optical Tweezers and FF-OCT

      Gwangju Institute of Science and recently proposed a label-free depth-resolved tomographic scheme for imaging a single live cell in fluid. This approach utilizes a modified time-domain full-field optical coherence tomography (FF-OCT) system combined with an optical tweezer technique. The optical trap for holding a moving specimen is made by tightly focusing a 1064 nm Q -switching pulsed laser beam with a 1.0 NA microscope objective in the sample arm of the FF-OCT part. By cosharing the probe for both systems, the optical actions of trapping and cellular resolution tomographic imaging could be achieved simultaneously. Feasibility of the combined system ...

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    8. Tomographic imaging of a suspending single live cell using optical tweezer-combined full-field optical coherence tomography

      Tomographic imaging of a suspending single live cell using optical tweezer-combined full-field optical coherence tomography

      We propose a label-free depth-resolved tomographic scheme for imaging a single live cell in fluid. This approach utilizes a modified time-domain full-field optical coherence tomography (FF-OCT) system combined with an optical tweezer technique. The optical trap for holding a moving specimen is made by tightly focusing a 1064 nm Q -switching pulsed laser beam with a 1.0 NA microscope objective in the sample arm of the FF-OCT part. By cosharing the probe for both systems, the optical actions of trapping and cellular resolution tomographic imaging could be achieved simultaneously. Feasibility of the combined system is demonstrated by imaging micron-sized ...

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    9. 2X2 Photonic Crystal Fiber Splitter For 800 Nm Spectral Domain Optical Coherence Tomography

      2X2 Photonic Crystal Fiber Splitter For 800 Nm Spectral Domain Optical Coherence Tomography

      We report the fabrication and performance of the 2x2 photonic crystal fiber (PCF) splitter that was designed as a single mode splitter at the 800 nm optical band and used as the beam splitter for a spectral domain optical coherence tomography system. The PCF splitter has been made by coupling PCFs to a planar lightwave circuit (PLC) splitter chip. The PLC splitter chip was fabricated to have a single mode property at the 800 nm wavelength band and the PCFs were securely connected to the PLC chip through PCF block arrays having lithographically fabricated V grooves. The core size of ...

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    10. Combined swept-source optical coherence tomography and fluorescence spectroscopy system

      Combined swept-source optical coherence tomography and fluorescence spectroscopy system

      We report a combined swept source optical coherence tomography (SSOCT) and fluorescence spectroscopy (FS) system for multimodal measurements of biochemical information and internal structures with fast imaging speed. The FS probe composed of a double clad fiber (DCF) coupler is adopted into the single mode fiber based SSOCT system. Here, the DCF coupler acts as a FS system as well as a multifunctional probe for the SSOCT-FS system. The performances of the single-unit SSOCT-FS system is confirmed by monitoring the fluorescence signal from photosensitizer in cancerous region of in-vivo rat and by imaging the internal structures of same region with ...

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    1-10 of 10
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  2. Topics in the News

    1. (10 articles) Kwan Seob Park
    2. (9 articles) Gwangju Institute of Science and Technology
    3. (8 articles) Byeong Ha Lee
    4. (7 articles) Tae Joong Eom
    5. (4 articles) Woo June Choi
    6. (2 articles) Ju Wan Kim
    7. (2 articles) Jun Geun Shin
    8. (2 articles) Myeong Jin Ju
    9. (2 articles) Myoung-Kyu Oh
    10. (1 articles) Seon Young Ryu
    11. (1 articles) British Columbia Cancer Agency
    12. (1 articles) Shanghai Jiao Tong University
    13. (1 articles) Singapore Eye Research Institute
    14. (1 articles) Simon Fraser University
    15. (1 articles) Columbia University
    16. (1 articles) Stephen Lam
    17. (1 articles) Pierre M. Lane
    18. (1 articles) Tien Yin Wong
    19. (1 articles) Giuseppe Querques
    20. (1 articles) Francesco Bandello
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    Combined swept-source optical coherence tomography and fluorescence spectroscopy system 2X2 Photonic Crystal Fiber Splitter For 800 Nm Spectral Domain Optical Coherence Tomography Tomographic imaging of a suspending single live cell using optical tweezer-combined full-field optical coherence tomography Feature Of The Week 8/26/12: Gwangju Institute of Science and Technology Investigate Tomography Imaging of Single Living Cell Using Optical Tweezers and FF-OCT Polarization sensitive full-field optical coherence tomography based on bi-stable polarizaton switch Single-camera polarization-sensitive full-field optical coherence tomography with polarization switch Real-time stroboscopic full-field optical coherence tomography based on graphics processing unit Deep brain optical coherence tomography angiography in mice: in vivo, noninvasive imaging of hippocampal formation Buffered polarization diverse detection for single-camera polarization-sensitive optical coherence tomography Angiographic Imaging of an In Vivo Mouse Brain as a Guiding Star for Automatic Digital Refocusing in OCT Line-field confocal optical coherence tomography-Practical applications in dermatology and comparison with established imaging methods Optical coherence tomography detection of changes in inner retinal and choroidal thicknesses in patients with early retinitis pigmentosa