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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
Editor in Chief :
Shin, Jung Hoon
Volume & Issues
Volume 19, Issue 6 - Dec 2015
Volume 19, Issue 5 - Oct 2015
Volume 19, Issue 4 - Aug 2015
Volume 19, Issue 3 - Jun 2015
Volume 19, Issue 2 - Apr 2015
Volume 19, Issue 1 - Feb 2015
Selecting the target year
Influence of Diverse Atmospheric Conditions on Optical Properties of a Pulse Laser in a Time-of-Flight Laser Range Finder
Shim, Young Bo ; Kwon, Oh-Jang ; Choi, Hyun-Yong ; Han, Young-Geun ;
Journal of the Optical Society of Korea, volume 19, issue 1, 2015, Pages 1~6
DOI : 10.3807/JOSK.2015.19.1.001
We investigate the propagation characteristics of a pulse laser in a time-of-flight laser range finder (TOF-LRF) system with variations in atmospheric conditions, such as temperature, pressure, relative humidity, and the concentration of
. The measurement error of distance related with the group velocity change in the TOF-LRF system is analyzed by considering the refractive index of the standard atmosphere with variations in atmospheric conditions. The dependence of the pulse width broadening induced by chromatic dispersion of the standard atmosphere on the operating wavelength and the initial pulse width of the light sources is discussed. The transmission of air with variations in the relative humidity or the concentration of
is analyzed by using different values of absorption coefficients depending on the operation wavelength of the light source in the TOF-LRF system.
Half mJ Supercontinuum Generation in a Telecommunication Multimode Fiber by a Q-switched Tm, Ho:YVO
Zhou, Renlai ; Ren, Jiancun ; Lou, Shuli ; Ju, Youlun ; Wang, Yuezhu ;
Journal of the Optical Society of Korea, volume 19, issue 1, 2015, Pages 7~12
DOI : 10.3807/JOSK.2015.19.1.007
broadband mid-infrared (IR) supercontinuum (SC) generation in telecommunication multimode fiber (MMF) directly pumped by a
nanosecond Q-switched Tm,
laser is demonstrated. An average output power of 3.64 W is obtained in the band of ~1900 to ~2600 nm, and the corresponding optic-to-optic conversion efficiency is 67% by considering the coupling efficiency. The spectrum has extremely high flatness with negligible intensity variation (<2%) in the wavelength interval of ~2070 to ~2475 nm. The SC long-wavelength edge is limited by the silicon glass material loss, and by optimizing the MMF length, the SC spectrum could extend out to
. The output SC pulse shapes are measured at different output powers, and no splits are found. The SC laser beam is nearly diffraction limited with an
measured by the traveling knife-edge method, and the laser beam spot is monitored by an infrared vidicon camera.
Efficient Logical Topology Design Considering Multiperiod Traffic in IP-over-WDM Networks
Li, Bingbing ; Kim, Young-Chon ;
Journal of the Optical Society of Korea, volume 19, issue 1, 2015, Pages 13~21
DOI : 10.3807/JOSK.2015.19.1.013
In recent years energy consumption has become a main concern for network development, due to the exponential increase of network traffic. Potential energy savings can be obtained from a load-adaptive scheme, in which a day can be divided into multiple time periods according to the variation of daily traffic patterns. The energy consumption of the network can be reduced by selectively turning off network components during the time periods with light traffic. However, the time segmentation of daily traffic patterns affects the energy savings when designing multiperiod logical topology in optical wavelength routed networks. In addition, turning network components on or off may increase the overhead of logical topology reconfiguration (LTR). In this paper, we propose two mixed integer linear programming (MILP) models to design the optimal logical topology for multiple periods in IP-over-WDM networks. First, we formulate the time-segmentation problem as an MILP model to optimally determine the boundaries for each period, with the objective to minimize total network energy consumption. Second, another MILP formulation is proposed to minimize both the overall power consumption (PC) and the reconfiguration overhead (RO). The proposed models are evaluated and compared to conventional schemes, in view of PC and RO, through case studies.
Improving Phase Contrast of Digital Holographic Microscope using Spatial Light Modulator
Le, Thanh Bang ; Piao, Meilan ; Jeong, Jong-Rae ; Jeon, Seok-Hee ; Kim, Nam ;
Journal of the Optical Society of Korea, volume 19, issue 1, 2015, Pages 22~28
DOI : 10.3807/JOSK.2015.19.1.022
We propose a new method for improving the phase contrast of a multiphase digital holographic microscope using a spatial light modulator (SLM). Using the SLM as the annulus, our method improves the light contrast of the object edge to achieve higher accuracy. We demonstrate a digital holographic microscopy technique that provides a 30% improvement in the phase contrast compared to conventional microscopy, which utilizes a mechanical annulus. The phase-contrast improvement allows the 3D reconstructed hologram to be determined more precisely.
Image-Quality Enhancement for a Holographic Wavefront Color Printer by Adaptive SLM Partitioning
Hong, Sunghee ; Stoykova, Elena ; Kang, Hoonjong ; Kim, Youngmin ; Hong, Jisoo ; Park, Joosup ; Park, Kiheon ;
Journal of the Optical Society of Korea, volume 19, issue 1, 2015, Pages 29~37
DOI : 10.3807/JOSK.2015.19.1.029
The wavefront printer records a volume-reflection hologram as a two-dimensional array of elemental holograms from computer-generated holograms (CGHs) displayed on a spatial light modulator (SLM). The wavefront coming from the object is extracted by filtering in the spatial-frequency domain. This paper presents a method to improve color reproduction in a wavefront printer with spatial division of exposures at primary colors, by adaptive partitioning of the SLM in accordance with the color content encoded in the input CGHs, and by the controllable change of exposure times for the recording of primary colors. The method is verified with a color wavefront printer with demagnification of the object beam. The quality of reconstruction achieved by the proposed method proves its efficiency in eliminating the stripe artifacts that are superimposed on reconstructed images in conventional mosaic recording.
Analysis of the Different Influences of Additive or Subtractive Three-dimensional Crosstalk on the Level of the Visual Fatigue
Park, Minyoung ; Kim, Joohwan ; Choi, Hee-Jin ;
Journal of the Optical Society of Korea, volume 19, issue 1, 2015, Pages 38~44
DOI : 10.3807/JOSK.2015.19.1.038
Three-dimensional (3D) crosstalk is one of the main causes of visual fatigue and needs to be suppressed. The 3D crosstalk can be categorized into two different kinds according to its appearance-additive 3D crosstalk and subtractive 3D crosstalk. In this paper, we analyze the influence of different kinds of 3D crosstalk to the perceived level of visual fatigue in order to suppress the perceived 3D crosstalk effectively.
Model-Based Tabu Search Algorithm for Free-Space Optical Communication with a Novel Parallel Wavefront Correction System
Li, Zhaokun ; Zhao, Xiaohui ; Cao, Jingtai ; Liu, Wei ;
Journal of the Optical Society of Korea, volume 19, issue 1, 2015, Pages 45~54
DOI : 10.3807/JOSK.2015.19.1.045
In this study, a novel parallel wavefront correction system architecture is proposed, and a model-based tabu search (MBTS) algorithm is introduced for this new system to compensate wavefront aberration caused by atmospheric turbulence in a free-space optical (FSO) communication system. The algorithm flowchart is presented, and a simple hypothetical design for the parallel correction system with multiple adaptive optical (AO) subsystems is given. The simulated performance of MBTS for an AO-FSO system is analyzed. The results indicate that the proposed algorithm offers better performance in wavefront aberration compensation, coupling efficiency, and convergence speed than a stochastic parallel gradient descent (SPGD) algorithm.
Ultrahigh-Resolution Spectral Domain Optical Coherence Tomography Based on a Linear-Wavenumber Spectrometer
Lee, Sang-Won ; Kang, Heesung ; Park, Joo Hyun ; Lee, Tae Geol ; Lee, Eun Seong ; Lee, Jae Yong ;
Journal of the Optical Society of Korea, volume 19, issue 1, 2015, Pages 55~62
DOI : 10.3807/JOSK.2015.19.1.055
In this study we demonstrate ultrahigh-resolution spectral domain optical coherence tomography (UHR SD-OCT) with a linear-wavenumber (k) spectrometer, to accelerate signal processing and to display two-dimensional (2-D) images in real time. First, we performed a numerical simulation to find the optimal parameters for the linear-k spectrometer to achieve ultrahigh axial resolution, such as the number of grooves in a grating, the material for a dispersive prism, and the rotational angle between the grating and the dispersive prism. We found that a grating with 1200 grooves and an F2 equilateral prism at a rotational angle of
, in combination with a lens of focal length 85.1 mm, are suitable for UHR SD-OCT with the imaging depth range (limited by spectrometer resolution) set at 2.0 mm. As guided by the simulation results, we constructed the linear-k spectrometer needed to implement a UHR SD-OCT. The actual imaging depth range was measured to be approximately 2.1 mm, and axial resolution of
in air was achieved, corresponding to
in tissue (n = 1.35). The sensitivity was -91 dB with -10 dB roll-off at 1.5 mm depth. We demonstrated a 128.2 fps acquisition rate for OCT images with 800 lines/frame, by taking advantage of NVIDIA's compute unified device architecture (CUDA) technology, which allowed for real-time signal processing compatible with the speed of the spectrometer's data acquisition.
Fabrication of Large Area Photonic Crystals with Periodic Defects by One-Step Holographic Lithography
Ma, Jie ; Wong, Kam Sing ; Li, Shan ; Chen, Zhe ; Zhou, Jianying ; Zhong, Yongchun ;
Journal of the Optical Society of Korea, volume 19, issue 1, 2015, Pages 63~68
DOI : 10.3807/JOSK.2015.19.1.063
A one-step fabrication of a photonic crystal (PC) with functional defects is demonstrated. Using multi-beam phase-controlled holographic lithography with a diffracting optical element, large area one dimensional (1D) and two dimensional (2D) PCs with periodic defects were fabricated. The uniform area is up to
, and tens of defect channels have been introduced in the 1D and 2D PC structure. This technique gives rise to substantial reduction in the fabrication complexity and significant improvement in the spatial accuracy of introducing functional defects in photonic crystals. This method can also be used to design and fabricate three dimensional (3D) PCs with periodic defects.
In vivo Optical Coherence Tomography Imaging of the Mesothelium Using Developed Window Models
Ahn, Yeh-Chan ; Chae, Yu-Gyeong ; Hwang, Sang Seok ; Chun, Bong-Kwon ; Jung, Maan Hong ; Nam, Sung Jin ; Lee, Hae-Young ; Chung, Jae Min ; Oak, Chulho ; Park, Eun-Kee ;
Journal of the Optical Society of Korea, volume 19, issue 1, 2015, Pages 69~73
DOI : 10.3807/JOSK.2015.19.1.069
The mesothelium is an essential lining for maintaining the normal homeostasis of the closed body cavity and a central component of pathophysiologic processes. The mesothelium has been known as the end target for asbestos which induces asbestos-related lung diseases. Malignant mesothelioma (MM) is a rare and fatal neoplasm predominantly due to asbestos exposure. Adaptation of an advanced and reliable technology is necessary for early detection of MM because it is difficult to diagnose this disease in its early stages. Optical coherence tomography (OCT) provides cross-sectional images of micro-tissue structures with a resolution of
that can image the mesothelium with a thickness of
and, therefore, enable investigation of early development of MM. The mesothelium is typically located at the pleura and tunica vaginalis of the scrotum. In this study, we developed animal window models in the above two anatomical sites to visualize mesothelial layers within the mesothelium. OCT images at the two locations were also acquired.
Color Clustered Multiple-input Multiple-output Visible Light Communication
Han, Phyu Phyu ; Sewaiwar, Atul ; Tiwari, Samart V. ; Chung, Yeon-Ho ;
Journal of the Optical Society of Korea, volume 19, issue 1, 2015, Pages 74~79
DOI : 10.3807/JOSK.2015.19.1.074
A novel color clustered optical RGB multiple-input multiple-output (MIMO) system is presented. As visible light can be divided into three primary regions of red, green and blue, data can be modulated and transmitted separately using these three color clusters. Each color cluster comprised of 30 RGB LEDs is modulated using on-off-keying (OOK), and selection combining is performed at the receiver, producing a diversity effect within that color cluster. The simulations demonstrate that the proposed RGB MIMO VLC system provides high performance via a relatively simple design of MIMO. Moreover, the proposed system ensures sufficient illumination from LEDs and offers extended distance if more LEDs are applied.
Fabrication of Three-Dimensional Reflective White Pattern using Dry-Film Resist
Jun, Hwa Joon ; Na, Dae Gil ; Kwon, Young Hoon ; Kwon, Jin Hyuk ;
Journal of the Optical Society of Korea, volume 19, issue 1, 2015, Pages 80~83
DOI : 10.3807/JOSK.2015.19.1.080
White reflective patterns are very difficult to fabricate, due to the scattering and reflection of light, especially when the pattern size goes down to micron size. A reflective white barrier structure of height
was fabricated using dry-film resist as an intermediate reverse pattern. The reverse dry-film resist pattern was coated with an
layer by sputtering, to protect the resist from chemical attack by the radical molecules in UV white resin. The UV white resin was applied on the dry-film resist pattern and then cured with ultraviolet light. The fine three-dimensional reflective patterns were finished by removing the dry-film resist.
Fast Sub-aperture Stitching Algorithm Using Partial Derivatives
Chen, Yiwei ; Miao, Erlong ; Sui, Yongxin ; Yang, Huaijiang ;
Journal of the Optical Society of Korea, volume 19, issue 1, 2015, Pages 84~87
DOI : 10.3807/JOSK.2015.19.1.084
For large optical elements which are tested by many sub-apertures, it takes too much time for a sub-aperture stitching algorithm to get the stitching result. To solve this problem, we propose a fast sub-aperture stitching algorithm to quickly compensate for piston, tilt, and defocus errors. Moreover, the new algorithm is easy to understand and program. We use partial derivatives of measurement data to separately solve piston, tilt, and defocus errors. First, we show that the new algorithm has a lower time complexity than the currently used algorithm. Although simulation results indicate that the accuracy of the new algorithm is lower than the current algorithm in all 20 simulations, our experimental results validate the algorithm and show it is sufficiently accurate for general use.
Liquid Crystal Lens Array with Thermally Controllable Focal Length and Electrically Convertible Lens Type
Heo, Kyong Chan ; Kwon, Jin Hyuk ; Gwag, Jin Seog ;
Journal of the Optical Society of Korea, volume 19, issue 1, 2015, Pages 88~94
DOI : 10.3807/JOSK.2015.19.1.088
This paper reports the fabrication of a lenticular liquid crystal (LC) lens array with thermally tunable focus and with the function of a convertible lens type, using the surface structure of a UV-curable polymer and a twisted-nematic (TN) LC cell. The TN LC cell makes the LC lenticular lens function as a converging or diverging lens by controlling electrically the polarization of input light. Therefore, the focal lengths for both the converging and diverging lenses, which can be switched from the TN cell, can be tuned by changing the effective refractive index of the LC by Joule heating of the transparent electrode. As a result, the focal length of the lens with the E7 LC was changed continuously from 8.7 to 31.2 mm for the converging lens type and from -9.8 to -14.2 mm for the diverging lens when the temperature was increased from 25 to
Approach of Self-mixing Interferometry Based on Particle Swarm Optimization for Absolute Distance Estimation
Li, Li ; Li, Xingfei ; Kou, Ke ; Wu, Tengfei ;
Journal of the Optical Society of Korea, volume 19, issue 1, 2015, Pages 95~101
DOI : 10.3807/JOSK.2015.19.1.095
To accurately extract absolute distance information from a self-mixing interferometry (SMI) signal, in this paper we propose an approach based on a particle swarm optimization (PSO) algorithm instead of frequency estimation for absolute distance. The algorithm is utilized to search for the global minimum of the fitness function that is established from the self-mixing signal to find out the actual distance. A resolution superior to
in the range from 3 to 20 cm is obtained by experimental measurement, and the results demonstrate the superiority of the proposed approach in comparison with interpolated FFT. The influence of different external feedback strength parameters and different inertia weights in the algorithm is discussed as well.
Recovering the Colors of Objects from Multiple Near-IR Images
Kim, Ari ; Oh, In-Hoo ; Kim, Hong-Suk ; Park, Seung-Ok ; Park, Youngsik ;
Journal of the Optical Society of Korea, volume 19, issue 1, 2015, Pages 102~111
DOI : 10.3807/JOSK.2015.19.1.102
This paper proposes an algorithm for recovering the colors of objects from multiple near-infrared (near-IR) images. The International Commission on Illumination (CIE) color coordinates of objects are recovered from a series of gray images captured under multiple spectral near-IR illuminations using polynomial regression. The feasibility of the proposed algorithm is tested experimentally by using 24 color patches of the Color Rendition Chart. The experimental apparatus is composed of a monochrome digital camera without an IR cut-off filter and a custom-designed LED illuminator emitting multiple spectral near-IR illuminations, with peak wavelengths near the red edge of the visible band, namely at 700, 740, 780, and 860 nm. The average color difference between the original and the recovered colors for all 24 patches was found to be 11.1. However, if some particular patches with high value are disregarded, the average color difference is reduced to 4.2, and this value is within the acceptability tolerance for complex image on the display.
Retraction note: Alleviating Light Leakage in LCDs via Diverse Modifications of Polarizer Film
Jeon, Il ; Yoon, MinSung ; Lee, Je-Hoon ;
Journal of the Optical Society of Korea, volume 19, issue 1, 2015, Pages 112~112
DOI : 10.3807/JOSK.2015.19.1.112