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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Optical Society of Korea
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Journal DOI :
Optical Society of Korea
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Volume & Issues
Volume 18, Issue 6 - Dec 2014
Volume 18, Issue 5 - Oct 2014
Volume 18, Issue 4 - Aug 2014
Volume 18, Issue 3 - Jun 2014
Volume 18, Issue 2 - Apr 2014
Volume 18, Issue 1 - Feb 2014
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Design and Simulation a New Unique-Slit Reticle for Pulsed Infrared Seekers
Yasin, Sair Alcekh ; Erfanian, Ali Reza ; Mosavi, Mohammad Reza ; Mohammadi, Ali ;
Journal of the Optical Society of Korea, volume 18, issue 1, 2014, Pages 1~8
DOI : 10.3807/JOSK.2014.18.1.001
Spin reticle infrared seekers have good linearity, and the pulse-modulated reticle seekers have good digital characteristics for anti-jamming processing. A basic design for a spin pulse-modulated reticle is introduced. This design uses the rotating design of the optical system in the spin infrared seekers and an improved design of the reticle in the pulse-modulated seekers. The reticle contains a unique well-designed slit to produce one pulse for each target in the spinning period. The target data will be carried by the unique pulse parameters. A simulation tool is implemented using the MATLAB packages for analyzing and evaluating the new design.
Effect of Sunlight Polarization on the Absorption Efficiency of V-shaped Organic Solar Cells
Kang, Kyungnam ; Kim, Jungho ;
Journal of the Optical Society of Korea, volume 18, issue 1, 2014, Pages 9~14
DOI : 10.3807/JOSK.2014.18.1.009
We numerically investigate the effect of sunlight polarization on the absorption efficiency of V-shaped organic solar cells (VOSCs) using the finite element method (FEM). The spectral distribution of absorbance and the spatial distribution of power dissipation are calculated as a function of the folding angle for s-and p-polarized light. The absorption enhancement caused by the light-trapping effect was more pronounced for s-polarized light at folding angles smaller than
, where s-polarized light has a relatively larger reflectance than p-polarized light. On the other hand, the absorption efficiency for p-polarized light is relatively larger for folding angles larger than
, where the smaller reflectance at the interface of the VOSC is more important in obtaining high absorption efficiency.
Measurement of Multimode Fiber Bandwidth by the Fourth-Order Spectra of Amplified Spontaneous Emission
Moon, Sucbei ; Kim, Dug Young ;
Journal of the Optical Society of Korea, volume 18, issue 1, 2014, Pages 15~22
DOI : 10.3807/JOSK.2014.18.1.015
We present a novel bandwidth measurement scheme for multimode optical fibers. Amplified spontaneous emission (ASE) radiation was utilized for a source of intrinsically modulated light with a wide modulation bandwidth. In our measurement scheme, the continuous-wave (CW) ASE light that passed through a multimode fiber (MMF) under test was analyzed by the fourth-order power with a high-speed photodetector and an electric spectrum analyzer. The modulation transfer function of the multimode fiber could be directly measured with the photoelectric spectra in the modulation frequency domain. The measurement result of our method was experimentally compared to that of the conventional measurement scheme based on the impulse response measurement. It has been found that our scheme provides a stable measurement means of MMF characterization that is suitable for the field testing due to the simplicity of the system.
Evaluation of a Corrected Cam for an Interchangeable Lens with a Distance Window
Kim, Jin Woo ; Ryu, Jae Myung ; Jo, Jae Heung ; Kim, Young-Joo ;
Journal of the Optical Society of Korea, volume 18, issue 1, 2014, Pages 23~31
DOI : 10.3807/JOSK.2014.18.1.023
Recently, the number of camera companies that produce commercializing interchangeable lens systems such as digital single lens reflex (DSLR) and compact system camera (CSC) lenses has been gradually increasing. These interchangeable lenses have various kinds of lenses with distinct specifications. In particular, the distance window among these specifications is the function most preferred by customers. Mechanical manual zoom and manual focus in these high end camera lenses with a distance window are in particular desirable specifications and are required for product quality. However, the AF lens group is linked to the zoom cam and moves. Because the AF lens group moves along with the object distance, we can not realize the distance window with only zoom locus calculation. In this paper, in order to solve the problem, we suggest an optical calculation method for a corrected AF zoom cam for an interchangeable lens with a distance window to achieve product differentiation and analyze the error in the calculation.
A Tangible Floating Display System for Interaction
Kim, Youngmin ; Kang, Hoonjong ; Ahn, Yangkeun ; Choi, Kwang-Soon ; Park, Byoungha ; Hong, Sunghee ; Jung, Kwang-Mo ;
Journal of the Optical Society of Korea, volume 18, issue 1, 2014, Pages 32~36
DOI : 10.3807/JOSK.2014.18.1.032
A tangible floating display that can provide different perspective views without special glasses being introduced. The proposed system can display perspective floating images in the space in front of the system with the help of concave mirrors. In order to avoid wearing special equipment to interact and deliver the sense of touch, the proposed system adopted an ultrasound focusing technology. For providing an immersive experience to the viewers, the proposed system consists of a tangible floating display system and a multiple-view imaging system for generating three lenticular displays in front of the users.
Unambiguous 3D Surface Measurement Method for a Micro-Fresnel Lens-Shaped Lenticular Lens Based on a Transmissive Interferometer
Yoon, Do-Young ; Kim, Tai-Wook ; Kim, Minsu ; Pahk, Heui-Jae ;
Journal of the Optical Society of Korea, volume 18, issue 1, 2014, Pages 37~44
DOI : 10.3807/JOSK.2014.18.1.037
The use of a laser interferometer as a metrological tool in micro-optics measurement is demonstrated. A transmissive interferometer is effective in measuring an optical specimen having a high angle slope. A configuration that consists of an optical resolution of 0.62 micron is adapted to measure a specimen, which is a micro-Fresnel lens-shaped lenticular lens. The measurement result shows a good repeatability at each fraction of facets, however, a reconstruction of the lens shape profile is disturbed by a known problem of
-ambiguity. To solve this
-ambiguity problem, we propose a two-step phase unwrapping method. In the first step, an unwrapped phase map is obtained by using a conventional unwrapping method. Then, a proposed unwrapping method based on the shape modeling is applied to correct the wrongly unwrapped phase. A measured height of each facet is compared with a profile result measured by AFM.
Luminescent Properties of BaSi
Phosphor Film Fabricated by Spin-Coating of Ba-Eu Precursor on SiO
Park, Je Hong ; Kim, Jong Su ; Kim, Jong Tae ;
Journal of the Optical Society of Korea, volume 18, issue 1, 2014, Pages 45~49
DOI : 10.3807/JOSK.2014.18.1.045
phosphor films were synthesized by heat treatment of spin-coated BaO:Eu on
glass. We investigated luminescence-structure properties of these phosphor films as a function of heat-treatment temperature. From x-ray diffraction patterns, our
phosphor films revealed that (111)- and (204)-crystal planes of
crystal were dominantly increased with an increase of heat-treatment temperature. Photoluminescence intensities of
phosphor films were increased with amount of these crystal planes. It can be explained that
ions were stably occupied at specific crystal orientation of
crystal, enhancing the luminescent intensities of
phosphor films. In addition, our
phosphor films had transmittance of 70% at 510 nm,.due to the dense morphology and specific crystallinity of
Damage Profile of HDPE Polymer using Laser-Induced Plasma
Tawfik, Walid ; Farooq, W. Aslam ; Alahmed, Z.A. ;
Journal of the Optical Society of Korea, volume 18, issue 1, 2014, Pages 50~54
DOI : 10.3807/JOSK.2014.18.1.050
In this paper we studied the laser-induced crater depth, mass, and emission spectra of laser-ablated high-density polyethylene (HDPE) polymer using the laser-induced plasma spectroscopy (LIPS) technique. This study was performed using a Nd:YAG laser with 100 mJ energy and 7 ns pulse width, focused normal to the surface of the sample. The nanoscale change in ablated depth versus number of laser pulses was studied. By using scanning electron microscope (SEM) images, the crater depth and ablated mass were estimated. The LIPS spectral intensities were observed for major and minor elements with depth. The comparison between the LIPS results and SEM images showed that LIPS could be used to estimate the crater depth, which is of interest for some applications such as thin-film lithography measurements and online measurements of thickness in film deposition techniques.
Multimodal Imaging of Sarcopenia using Optical Coherence Tomography and Ultrasound in Rat Model
Jeon, Byeong Hwan ; Chae, Yu-Gyeong ; Hwang, Sang Seok ; Kim, Dong Kyu ; Oak, Chulho ; Park, Eun-Kee ; Ahn, Yeh-Chan ;
Journal of the Optical Society of Korea, volume 18, issue 1, 2014, Pages 55~59
DOI : 10.3807/JOSK.2014.18.1.055
Sarcopenia, or reduced muscle mass and volume, is due to various factors such as senile change, neuronal degeneration, drug, malignancy, and sepsis. Sarcopenia with the aging process has been evidenced by the decline in muscle mass by 0.5 to 1% per year with 3-5% reduction in muscle strength for 10 years between the ages of 40 and 50, and a 1-2% of decline of mass every year in people aged 60-70. Therefore, early diagnosis and understanding the mechanism of sarcopenia are crucial in the prevention of muscle loss. However, it is still difficult to image changes of muscle microstructure due to a lack of techniques. In this study, we developed an animal model using denervated rats to induce a rapid atrophy in the tibialis anterior (TA) and imaged its structural changes using optical coherence tomography (OCT) along with histologic and ultrasound analyses. Ultrasound showed changes of overall muscle size. Histology revealed that the atrophic TA muscle displayed an increased size variability of muscle fiber and inflammatory changes. Three dimensional OCT imaged the changes of perimysial grid and muscle fiber structure in real time without sacrifice. These observed advantages of multimodal imaging using OCT and ultrasound would provide clinical benefits in the diagnosis of sarcopenia.
Diffraction-Limited High-Power Single-Cycle Terahertz Pulse Generation in Prism-Cut LiNbO
for Precise Terahertz Applications
Baek, In Hyung ; Kang, Bong Joo ; Jeong, Young Uk ; Rotermund, Fabian ;
Journal of the Optical Society of Korea, volume 18, issue 1, 2014, Pages 60~64
DOI : 10.3807/JOSK.2014.18.1.060
We report the generation of 3.3-mW single-cycle terahertz (THz) pulses at 1-kHz repetition rate via optical rectification in MgO-doped prism-cut stoichiometric LiNbO3. Efficient pulse-front tilting of 800-nm pulses was realized by an optimized single-lens focusing scheme for radially-symmetric propagation of THz beams. In this geometry, nearly-diffraction-limited THz Gaussian beams with electric field strength as high as 350 kV/cm were generated. The pump-to-THz energy conversion efficiency of
and the extremely high signal-to-noise ratio of ~1:15000 achieved are among the best results for 1-kHz single-cycle terahertz pulse generation ever demonstrated in room temperature operation.
Performance Analysis of a High-Speed All-Optical Subtractor using a Quantum-Dot Semiconductor Optical Amplifier-Based Mach-Zehnder Interferometer
Salehi, Mohammad Reza ; Taherian, Seyed Farhad ;
Journal of the Optical Society of Korea, volume 18, issue 1, 2014, Pages 65~70
DOI : 10.3807/JOSK.2014.18.1.065
This paper presents the simulation and design of an all-optical subtractor using a quantum-dot semiconductor optical amplifier Mach-Zehnder interferometer (QD-SOA MZI) structure consisting of two cascaded switches, the first of which produces the differential bit. Then the second switch produces the borrow bit by using the output of the first switch and the subtrahend data stream. Simulation results were obtained by solving the rate equations of the QD-SOA. The effects of QD-SOA length, peak power and current density have been investigated. The designed gate can operate at speeds of over 250 Gb/s. The simulation results demonstrate a high extinction ratio and a clear and wide-opening eye diagram.
Design and Fabrication of Multi-Focusing Microlens Array with Different Numerical Apertures by using Thermal Reflow Method
Park, Min-Kyu ; Lee, Ho Jun ; Park, Ji-Sub ; Kim, Mugeon ; Bae, Jeong Min ; Mahmud, Imtiaz ; Kim, Hak-Rin ;
Journal of the Optical Society of Korea, volume 18, issue 1, 2014, Pages 71~77
DOI : 10.3807/JOSK.2014.18.1.071
We present design and fabrication of a multi-focusing microlens array (MLA) using a thermal reflow method. To obtain multi-focusing properties with different numerical apertures at the elemental lens of the MLA, double-cylinder photoresist (PR) structures with different diameters were made within the guiding pattern with both photolithographic and partial developing processes. Due to the base PR layer supporting the thermal reflow process and the guiding structure, the thermally reflowed PR structure had different radii of curvatures with lens shapes that could be precisely modeled by the initial volume of the double-cylinder PR structures. Using the PR template, the hexagonally packed multi-focusing MLA was made via the replica molding method, which showed four different focal lengths of 0.9 mm, 1.1 mm, 1.6 mm, and 2.5 mm, and four different numerical apertures of 0.1799, 0.2783, 0.3973, and 0.4775.
Advanced Patterned Vertical Aligned Nematic Mode to Elevate Transmittance
Gwag, Jin Seog ;
Journal of the Optical Society of Korea, volume 18, issue 1, 2014, Pages 78~81
DOI : 10.3807/JOSK.2014.18.1.078
This paper presents an advanced patterned vertical aligned nematic liquid crystal (APVA) mode as a way of improving the transmittance of the conventional patterned, vertically-aligned nematic liquid crystal (PVA) mode. The APVA was characterized by multi-electrodes, which play an important role in generating a horizontal electric field that prevents LC disclination in the vicinity of the middle region of electrodes between top and bottom slits in PVA mode. The proposed APVA mode focused on improving dramatically the transmittance with excellent image quality. In the simulation, the APVA mode improved the transmittance by more than 22%, compared to the conventional VA modes. Therefore, it is useful to upgrade the LCD display quality.
Simulation and Optimization of Nonperiodic Plasmonic Nano-Particles
Akhlaghi, Majid ; Emami, Farzin ; Sadeghi, Mokhtar Sha ; Yazdanypoor, Mohammad ;
Journal of the Optical Society of Korea, volume 18, issue 1, 2014, Pages 82~88
DOI : 10.3807/JOSK.2014.18.1.082
A binary-coupled dipole approximation (BCDA) is described for designing metal nanoparticles with nonperiodic structures in one, two, and three dimensions. This method can be used to simulate the variation of near- and far-field properties through the interactions of metal nanoparticles. An advantage of this method is in its combination with the binary particle swarm optimization (BPSO) algorithm to find the best array of nanoparticles from all possible arrays. The BPSO algorithm has been used to design an array of plasmonic nanospheres to achieve maximum absorption, scattering, and extinction coefficient spectra. In BPSO, a swarm consists of a matrix with binary entries controlling the presence ('1') or the absence ('0') of nanospheres in the array. This approach is useful in optical applications such as solar cells, biosensors, and plasmonic nanoantennae, and optical cloaking.
Determination of the Perceived Contrast Compensation Ratio for a Wide Range of Surround Luminance
Baek, Ye Seul ; Kim, Hong-Suk ; Park, Seung-Ok ;
Journal of the Optical Society of Korea, volume 18, issue 1, 2014, Pages 89~94
DOI : 10.3807/JOSK.2014.18.1.089
It is established that the perceived image contrast is affected by surround luminance. In order to get the same perceived image contrast, the optimum surround compensation ratios for those surround conditions is needed. Much research has been performed for dark, dim, and average surrounds. In this study, a wide range of surround luminance from dark up to
was considered. Using magnitude estimation method, the change in perceived brightness of six test stimuli was measured under seven surround conditions; dark, dim, 2 levels of average, bright, and 2 levels of over-bright surrounds. To drive the perceived image contrast from the perceived brightness, two different definitions of contrast were tested. Their calculated results were compared with the visual data of our previous work. And to conclude, the perceived contrast compensation ratios were 1:1.11:1.2 for average, dim and dark surrounds. These were close to CIECAM02 model (1:1.17:1.31). Besides, for average, bright, over-bright1 and over-bright2 surrounds the ratios 1:1.17:1.42:1.69 were determined. For intermediate or more extreme surround conditions, the compensation ratio was obtained from the linear interpolation or extrapolation.