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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Journal of the Optical Society of Korea
Journal Basic Information
Journal DOI :
Optical Society of Korea
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Volume & Issues
Volume 12, Issue 4 - Dec 2008
Volume 12, Issue 3 - Sep 2008
Volume 12, Issue 2 - Jun 2008
Volume 12, Issue 1 - Mar 2008
Selecting the target year
Miniband Structure of Quantum Dots based on GaN/AlN Nanowire Arrays
Jung, Oui-Chan ; Cho, Hyung-Uk ; Yi, Jong-Chang ;
Journal of the Optical Society of Korea, volume 12, issue 2, 2008, Pages 65~68
DOI : 10.3807/JOSK.2008.12.2.065
The miniband structure of a quantum dot lattice based on GaN/AlN nanowire arrays has been investigated using the finite element method and Floquet theorem. The quantum dot modes and the quantum wire modes in the nanowire arrays were graphically verified. The optimum geometries of GaN/AlN quantum wire arrays were investigated by using a correlation between the width of nanowires and the separation of the minibandgap which is to be larger than the thermal energy at room temperature.
IPTV Delivery Architecture in 10G EPONs using ONU-Based Multicast Emulation
Choi, Su-Il ;
Journal of the Optical Society of Korea, volume 12, issue 2, 2008, Pages 69~78
DOI : 10.3807/JOSK.2008.12.2.069
EPONs are a low cost, high speed solution to the bottleneck problem of broadband access networks. To support point-to-point and shared LAN emulation, EPONs use the multi-point control protocol (MPCP), which uses logical link identification (LLID) forframe tagging and filtering between the OLT and ONUs. In this paper, ONU-based multicast or multiple shared LAN emulation for IPTV services is proposed using logical group identification (LGID). Using ONUbased VLAN services, EPONs can support separate and secure connections between providers and subscribers in a simple manner. Also, differentiated IPTV channel packages can be delivered through EPONs by implementing ONU-based VLAN and IGMP snooping mechanisms.
Fisheye Lens for Image Processing Applications
Kweon, Gyeong-Il ; Choi, Young-Ho ; Laikin, Milton ;
Journal of the Optical Society of Korea, volume 12, issue 2, 2008, Pages 79~87
DOI : 10.3807/JOSK.2008.12.2.079
We have developed a miniature fisheye lens with
field of view operating simultaneously in the visible and the near infrared wavelengths. The modulation transfer function characteristic for the visible wavelength is sufficient for a mega-pixel-grade image sensor. The lens also has a fair resolution in the infrared wavelength region. The calibrated
distortion is less than 5%, and the relative illumination is over 90%. In consequence, a sharp wide-angle image can be obtained which is uniform in brightness over the entire range of field angles. The real image heights for the visible and the near infrared wavelengths have been fitted to polynomial functions of incidence angle with sub-pixel accuracies. Combined with the near equidistance projection scheme of the lens, this lens can be advantageously employed in various image-processing applications requiring a wide-angle lens.
Photon Counting Linear Discriminant Analysis with Integral Imaging for Occluded Target Recognition
Yeom, Seok-Won ; Javidi, Bahram ;
Journal of the Optical Society of Korea, volume 12, issue 2, 2008, Pages 88~92
DOI : 10.3807/JOSK.2008.12.2.088
This paper discusses a photon-counting linear discriminant analysis (LDA) with computational integral imaging (II). The computational II method reconstructs three-dimensional (3D) objects on the reconstruction planes located at arbitrary depth-levels. A maximum likelihood estimation (MLE) can be used to estimate the Poisson parameters of photon counts in the reconstruction space. The photon-counting LDA combined with the computational II method is developed in order to classify partially occluded objects with photon-limited images. Unknown targets are classified with the estimated Poisson parameters while reconstructed irradiance images are trained. It is shown that a low number of photons are sufficient to classify occluded objects with the proposed method.
Conditions for Moire Free Contact-Type 3 Dimensional Displays
Song, Yoon-Chul ; Saveljev, Vladimir V. ; Son, Jung-Young ; Yeom, Seok-Won ; Vashpanov, Yu. A. ;
Journal of the Optical Society of Korea, volume 12, issue 2, 2008, Pages 93~97
DOI : 10.3807/JOSK.2008.12.2.093
The superposing angle of the viewing zone forming optics and the display panel in the contact type 3 dimensional imaging systems for minimizing
is found for a rectangular shape pixel with different aspect ratios. The angles are
for square shape pixels and
for the rectangular with aspect ratio 2. These angles result in the
with the smallest period for the respective aspect ratio. The effectiveness of the angles is also experimentally demonstrated.
Evaluation of Morphological Changes in Degenerative Cartilage Using 3-D Optical Coherence Tomography
Youn, Jong-In ;
Journal of the Optical Society of Korea, volume 12, issue 2, 2008, Pages 98~102
DOI : 10.3807/JOSK.2008.12.2.98
Optical Coherence Tomography (OCT) is an important noninvasive medical imaging technique that can reveal subsurface structures of biological tissue. OCT has demonstrated a good correlation with histology in sufficient resolution to identify morphological changes in articular cartilage to differentiate normal through progressive stages of degenerative joint disease. Current OCT systems provide individual cross-sectional images that are representative of the tissue directly under the scanning beam, but they may not fully demonstrate the degree of degeneration occurring within a region of a joint surface. For a full understanding of the nature and degree of cartilage degeneration within a joint, multiple OCT images must be obtained and an overall assessment of the joint surmised from multiple individual images. This study presents frequency domain three-dimensional (3-D) OCT imaging of degenerative joint cartilage extracted from bovine knees. The 3-D OCT imaging of articular cartilage enables the assembly of 126 individual, adjacent, rapid scanned OCT images into a full 3-D image representation of the tissue scanned, or these may be viewed in a progression of successive individual two-dimensional (2-D) OCT images arranged in 3-D orientation. A fiber-based frequency domain OCT system that provides cross-sectional images was used to acquire 126 successive adjacent images for a sample volume of
. The axial resolution was
in air. The 3-D OCT was able to demonstrate surface topography and subsurface disruption of articular cartilage consistent with the gross image as well as with histological cross-sections of the specimen. The 3-D OCT volumetric imaging of articular cartilage provides an enhanced appreciation and better understanding of regional degenerative joint disease than may be realized by individual 2-D OCT sectional images.
Vector and Scalar Modes in Coherent Mode Representation of Electromagnetic Beams
Kim, Ki-Sik ;
Journal of the Optical Society of Korea, volume 12, issue 2, 2008, Pages 103~106
DOI : 10.3807/JOSK.2008.12.2.103
It is shown that the two mode representations, one with vector modes and the other with scalar modes, for the cross spectral density matrices of electromagnetic beams are equivalent to each other. In particular, we suggest a method to find the vector modes from the scalar modes and formulate the cross spectral density matrix as a correlation matrix.
Single-molecule Detection of Fluorescence Resonance Energy Transfer Using Confocal Microscopy
Kim, Sung-Hyun ; Choi, Don-Seong ; Kim, Do-Seok ;
Journal of the Optical Society of Korea, volume 12, issue 2, 2008, Pages 107~111
DOI : 10.3807/JOSK.2008.12.2.107
We demonstrated single-molecule fluorescence resonance energy transfer (FRET) from single donor-acceptor dye pair attached to a DNA with a setup based on a confocal microscope. Singlestrand DNAs were immobilized on a glass surface with suitable inter-dye distance. Energy transfer efficiency between the donor and the acceptor dyes attached to the DNA was measured with different lengths of DNA. Photobleaching of single dye molecule was observed and used as a sign of single-molecule detection. We could achieve high enough signal-to-noise ratio to detect the fluorescence from a single-molecule, which allows real-time observation of the distance change between single dye pairs in nanometer scale.
Mode Propagation in X-Ray Waveguides
Choi, J. ; Jung, J. ; Kwon, T. ;
Journal of the Optical Society of Korea, volume 12, issue 2, 2008, Pages 112~117
DOI : 10.3807/JOSK.2008.12.2.112
Single-mode propagation conditions of X-ray waveguides are investigated by numerical calculations in order to understand the importance of waveguide design parameters, such as core thickness and the optical constants of waveguide materials, on the transmission and coherence properties of the waveguide. The simulation code for mode analyzing is developed based on a numerical solution of the parabolic wave equation. The initial boundary value problem is solved numerically using a finite-difference scheme based on the Crank-Nicolson scheme. The E-field intensities in a core layer are calculated at an X-ray energy of 8.0 keV for air and beryllium(Be) core waveguides with different cladding layers such as Pt, Au, W, Ni and Si to determine the dependence on waveguide materials. The highest E-field intensity radiated at the exit of the waveguide is obtained from the Pt cladded beryllium core with a thickness of 20 nm. However, the intensity from the air core waveguide with Pt cladding reaches 64% of the Be-Pt waveguide. The dependence on the core thickness, which is the major parameter used to generate a single mode in the waveguide, is investigated for the air-Pt, and Be-Pt waveguides at an X-ray energy of 8.0 keV. The mode profiles at the exit are shown for the single mode at a thickness of up to 20 nm for the air-Pt and the Be-Pt waveguides.