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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Korean Journal of Optics and Photonics
Journal Basic Information
Journal DOI :
Optical Society of Korea
Editor in Chief :
Volume & Issues
Volume 20, Issue 6 - Dec 2009
Volume 20, Issue 5 - Oct 2009
Volume 20, Issue 4 - Aug 2009
Volume 20, Issue 3 - Jun 2009
Volume 20, Issue 2 - Apr 2009
Volume 20, Issue 1 - Feb 2009
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Design of Metal-Slit Fresnel Lens for Enhanced Coupling Efficiency
Park, Dong-Won ; Jung, Young-Jin ; Koo, Suk-Mo ; Yu, Sun-Kyu ; Park, Nam-Kyoo ; Jhon, Young-Min ; Lee, Seok ;
Korean Journal of Optics and Photonics, volume 20, issue 1, 2009, Pages 1~5
DOI : 10.3807/HKH.2009.20.1.001
Recently, much research has been done for to realizeing nano-scale photonic circuits based on photonic crystal, plasmonics and silicon photonics in order to overcome fundamental limits of electronic circuits. These limits include such as bottleneck of speed, and size that cannot be reduced. Even though several kinds of coupling schemes have been reported, coupling structures are still large when it is compared with the nano-scale optical circuit. In this paper, we proposed using a very thin Fresnel lens while shortening the focal length of the Fresnel lens as much as possible. We proposed, for the first time, to utilize metal slits that are able to use the optical coupling system between a nano-scale optical circuit and the standard single mode optical fiber for overcoming the limitation of focal length shortening of the Fresnel lens. Comparative study has been carried out with a FDTD simulation between normal and metal slit assisted Fresnel lens. From the result of simulation, we can achieve 65% coupling efficiency for the metal-slit Fresnel lens when the focal length of metal-slit Fresnel lens is just
. On the other hand, the coupling efficiency of the normal Fresnel lens is about 43%.
A Study for Stray Light Distribution of Mobile Phone Camera Consisting of Two Aspheric Lenses
Park, Kwang-Woo ; Lee, Jong-Ung ;
Korean Journal of Optics and Photonics, volume 20, issue 1, 2009, Pages 6~15
DOI : 10.3807/HKH.2009.20.1.006
A mobile phone camera consisting of two aspheric lenses is designed, and stray light distribution on the image plane is analyzed. We assume that most of the incident light is absorbed on the inner surfaces of the lens barrel and spacers, only a small fraction of the light is scattered uniformly. Assuming that 10% of the incident light is scattered on the barrel and spacers, the maximum value of stray light is 7.1% of the ideal image intensity. The result of analysis shows that stray light originated mostly from internal reflection on the ribs. The contributions of scattering by the barrel and spacers are relatively small. To reduce the internal reflection, thin absorbing plates are inserted between lenses, and the shapes of spacers are modified. After the redesigning of the lens barrel, the maximum value of stray light is reduced to 1.1% of the ideal image intensity.
Three-Dimensional Conversion of Two-Dimensional Movie Using Optical Flow and Normalized Cut
Jung, Jae-Hyun ; Park, Gil-Bae ; Kim, Joo-Hwan ; Kang, Jin-Mo ; Lee, Byoung-Ho ;
Korean Journal of Optics and Photonics, volume 20, issue 1, 2009, Pages 16~22
DOI : 10.3807/HKH.2009.20.1.016
We propose a method to convert a two-dimensional movie to a three-dimensional movie using normalized cut and optical flow. In this paper, we segment an image of a two-dimensional movie to objects first, and then estimate the depth of each object. Normalized cut is one of the image segmentation algorithms. For improving speed and accuracy of normalized cut, we used a watershed algorithm and a weight function using optical flow. We estimate the depth of objects which are segmented by improved normalized cut using optical flow. Ordinal depth is estimated by the change of the segmented object label in an occluded region which is the difference of absolute values of optical flow. For compensating ordinal depth, we generate the relational depth which is the absolute value of optical flow as motion parallax. A final depth map is determined by multiplying ordinal depth by relational depth, then dividing by average optical flow. In this research, we propose the two-dimensional/three-dimensional movie conversion method which is applicable to all three-dimensional display devices and all two-dimensional movie formats. We present experimental results using sample two-dimensional movies.
Image Stitching and Seamless Holographic Photo-Lithography for Large-Area Patterning
Lee, Joon-Sub ; Park, Woo-Jae ; Lee, Ji-Whan ; Song, Soek-Ho ; Lee, Sung-Jin ; Kim, Oui-Serg ;
Korean Journal of Optics and Photonics, volume 20, issue 1, 2009, Pages 23~28
DOI : 10.3807/HKH.2009.20.1.023
In this study, we propose an image stitching method for large-area holographic photo lithography. In this method, a hologram medium become a hologram mask for lithography. And the mask has information for stitched images. These images are recorded by signal images which are controlled with DMD (digital micro-mirror device), and serial hologram recording is achieved with a motorized linear stage. Using this method, fringe seams appear on the stitching area. To remove these fringe seams, double exposure holographic lithography is tried. Each stitched image is recorded and reconstructed with a different reference beam. The experiments confirm that fringe seams are removed.
Simultaneous Measurement of Thickness and Refractive Index of Transparent Material Using a Collimated Beam Having a Finite Radius
Park, Dae-Seo ; O, Beom-Hoan ; Park, Se-Geun ; Lee, El-Hang ; Lee, Seung-Gol ;
Korean Journal of Optics and Photonics, volume 20, issue 1, 2009, Pages 29~33
DOI : 10.3807/HKH.2009.20.1.029
We propose a new measuring technique based on optical low-coherence reflectometry that enables us to determine the refractive index and the geometrical thickness of a transparent sample by one-time scanning only. By passing a collimated beam having a finite size through the edge of the sample, the refractive index and the geometrical thickness can be determined simultaneously from the comparison of interferograms generated by two kinds of reflected beams. In this study, a refractive index could be determined with the accuracy of
, and its accuracy would be enhanced by using a more precise translator and a thicker sample.
Effect of Surface Improvement on Thin Film by In-Situ Laser Annealing Deposition
Lee, Se-Ho ; Yu, Yeon-Serk ;
Korean Journal of Optics and Photonics, volume 20, issue 1, 2009, Pages 34~40
DOI : 10.3807/HKH.2009.20.1.034
In-situ pulse laser (Nd-YAG, 2nd harmonics 532 nm) annealing used in physical vapor deposition of
and ZnS thin films was shown to be effective in improving their surface roughness properties. Total integrated scattering (TIS) measurements of
samples deposited on glass substrates revealed that the laser irradiation of films at an energy of approximately
at 532 nm with a repetition frequency of 10 Hz and pulse duration of 5 ns during the deposition resulted in total scatterings that were minimum. But in case of the ZnS samples, measurements revealed minimum total scattering at a laser energy of approximately
. Atomic Force Microscopy (AFM) has been used to evaluate the effect of pulse laser annealing on the surface roughness for thin film samples. The results were similar to the TIS measurements, indicating that surface roughness was decreased when the irradiated annealing pulse laser energy increased. But it also increased when the irradiated annealing pulse laser energy was over some limit that depended on the materials.
Single Mode Lasing Characteristics in Multimode Interferometer-Coupled Semiconductor Square Ring Resonators
Jeong, Dal-Hwa ; Moon, Hee-Jong ; Hyun, Kyung-Sook ;
Korean Journal of Optics and Photonics, volume 20, issue 1, 2009, Pages 41~47
DOI : 10.3807/HKH.2009.20.1.041
We report the spectral characteristics of Multimode Interferometer (MMI)-coupled semicondoctor square ring resonators. The epitaxial layers of the proposed semiconductor ring resonator consists of
GaInAsP-InP multiple quantum wells. The lasing characteristics were observed by varying the structure parameters of the MMI-coupled square ring resonators. It is concluded that the MMI-coupled scheme selects a single spectral lasing mode in the double square ring cavities.
Lossless Linear Polarization Rotator by Using a ECB Liquid Crystal Cell and a Quarter Wave Plate
Jo, Jae-Heung ;
Korean Journal of Optics and Photonics, volume 20, issue 1, 2009, Pages 48~52
DOI : 10.3807/HKH.2009.20.1.048
We make a simple electrically controllable linear polarization rotator over
without loss by using a thick ECB(electrically controlled birefringence) liquid crystal cell and a quarter wave plate at 514.5 nm wavelength. Its operating principle can be analyzed and explained by using simple polarization analysis and experimental data. We demonstrate that the degree of polarization of the rotator is 0.964 and the temporal variation for 1 week lies within
degree. We can easily solve the problem of nonlinearity of the dependence of the rotational angle of linear polarization on the applied voltage by changing the utilized voltage range or its fitting curve.
Study on Refractive Index and Thickness of Human Stem Cells by Using Imaging Ellipsometry
Choi, Joong-Kyu ; Shim, Woo-Young ; Lee, Gwang ; Kim, Sang-Youl ; Park, Sang-Uk ; CheGal, Won ; Cho, Hyun-Mo ; Cho, Yong-Jai ;
Korean Journal of Optics and Photonics, volume 20, issue 1, 2009, Pages 53~56
DOI : 10.3807/HKH.2009.20.1.053
We applied an ellipsometric technique to get quantitative information about the thickness and refractive index of human Mesenchymal Stem Cells (hMSCs). The images of ellipsometric constants
for the nucleus region and for the cell body region of hMSCs were obtained by using an Imaging Ellipsomter (IE) for their in vitro state. A numerical inversion method was applied to deduce the refractive index and the thickness of hMSCs from the measured
. Thus the images of the refractive index and those of the thickness of hMSCs for the nucleus region and for the cell body region are reported.
Enhancement of Light Guiding Efficiency in CMOS Image Sensor by Introducing an Optical Thin Film
Kang, Myung-Hoon ; Ko, Eun-Mi ; Lee, Je-Won ; Cho, Guan-Sik ;
Korean Journal of Optics and Photonics, volume 20, issue 1, 2009, Pages 57~60
DOI : 10.3807/HKH.2009.20.1.057
We consider introducing an optical thin film to the light guiding wall of a pixel in order to enhance the light guiding efficiency of a CMOS image sensor. Simulating the reflectance as a function of the incidence angle using the Essential Macleod program, we find that the range of total internal reflection is greatly increased for several materials. Particularly when air is chosen as the thin film material, the critical angle of total internal reflection could be shifted to about 50 degrees.