• Journal of the Korean Chemical Society
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• v.28 no.5
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• pp.271-278
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• 1984

Ellipsometric and reflectance measurements were made with magneto-optically self-nulling ellipsometer on the iron surface being passivated. The passivation was induced by abruptly changing potential of the mechanically polished high purity iron from the reduction potential to the oxidation potential in basic solutions. From the differences in the optical paramates(${\Delta},\;{\psi}$) and reflectance (R) between the reduced (film-free) and oxidized (film-covered) states, the thickness(${\tau}$) and optical constants (n, k) of the film in the early stage of its formation were computed as functions of pH and time. From the computed values, it was deduced that the properties of the anodic film did not undergo a drastic change with time which would indicate a transformation of the film before effective passivity is attained, and that the film reached its stady state within a few second. The thickness of anodic film was $14\;{\sim}\;23{\AA}$. The anodic films also seemed to have small values of optical absorption coefficient. The film formed in high pH environments had thinner and denser structure than that formed in low pH.

• Journal of Korean Ophthalmic Optics Society
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• v.18 no.3
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• pp.313-320
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• 2013

Purpose: This study compared the quantity of phoria for distance by new method with that by existing methods. Methods: For this study, it was selected to two existing phoria measurements, von Graefe and Maddox rod. And new method named "3D polarizing phoria measurement" was designed to measure the quantity of phoria using polarizing glasses and 3D display. Unlike existing measurement using polarized lens, newly considered method measured the quantity of phoria in condition removed perfect binocular fusion using field stop on apparatus and polarized lens. For using new method for distance, it was developed a phoria test chart. It supports three kinds of phoria measurements. Subjects were 12 (male 6, female 6). They had three phoria tests (1 sets) including new method. It was considered the effect of experimental order, so we tested all cases about experimental order. The number of cases was 6 sets, and the sample size in this experiment was 72 sets. For removing binocular fusion, lighting of the laboratory that was below 10 lx and the background color of phoria test chart was dark, RGB=(20, 20, 20). Results: Subjects were sorted into three groups. Samples with exophoria and orthophoria were 30 sets each, and those with esophoria were 12 sets. The quantity of phoria measured three tests differ from each other like "newmethod < von Graefe < Maddox rod", and there were statistically significant difference each other. Conclusions: This study has great significance in the sense that new method was the measurement with naturally removing binocular fusion without dizziness during the tests.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.3
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• pp.406-409
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• 2012

The classical electromagnetically-induced transparency(EIT)-like switching in metamaterial was experimentally and theoretically demonstrated in the microwave-frequency region. The metamaterial unit cell consists of two identical split-ring resonators, which are arranged on both sides of a dielectric substrate with asymmetry. It is found that the classical EIT-like switching can be achieved by changing the polarization of the incident electromagnetic wave. The results of this study are promising for practical applications.

• Journal of Korean Ophthalmic Optics Society
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• v.6 no.2
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• pp.155-160
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• 2001

To investigate the subjective refractive error with Von Graefe test. Maddox Rod test and polarizing lens test of Horizontal Heterophoria Measurement at distance on normal 109 subjects aged from 18 to 30 years old. The results were as follows: 1. Using Von Graefe Horizontal Heterophoria Measurement, they were measured 15% for orthophoria, 65% for exophoria and 20% for esophoria at distance. 2. Using Maddox Rod Horizontal Heterophoria Measurement, they were measured 14% for orthophoria, 57% for exophoria and 29% for esophoria at distance. 3. Using polarizing lens test of Horizontal Heterophoria Measurement, they were measured 15% for orthophoria, 72% for exophoria and 13% for esophoria at distance. 4. Each test average were $1.32{\Delta}BI$ for Von Graefe test, $0.88{\Delta}BI$ for Maddox Rod test and $1.76{\Delta}BI$ for polarizing lens test. 5. Patient's preference distribution were 44% for Von Graefe test, 28% for Maddox Rod test and 28% for polarizing lens test.

• Korean Journal of Optics and Photonics
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• v.26 no.6
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• pp.306-311
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• 2015

We report the characteristics of a single-wavelength-tunable fiber laser using a polymer waveguide Bragg grating (PWBG) wavelength filter. The output of the laser depends on environmental conditions, such as temperature and polarization states in the laser cavity. Wavelength tuning can be achieved, about 16.29 nm from 1548.24 nm to 1531.95 nm, according to the electric power applied to the PWBG wavelength filter. The achieved efficiency slope is about -0.16 nm/mW. A side-mode suppression ratio (SMSR) of more than 35 dB can be obtained by adjusting the polarization state in the laser cavity. A stable wavelength-tunable fiber laser can be achieved using the PWBG wavelength filter with a TEC module and a polarization-maintaining fiber.

• Proceedings of the KIEE Conference
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• 2004.07c
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• pp.2003-2005
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• 2004

본 논문에서는 패러데이 효과(Faraday effect)를 이용하여 초고압 전력설비에서 대전류 측정을 위한 광CT의 온도변화에 따른 특성에 대한 기초 연구를 하였다. 광원으로는 1310[nm] Laser Diode를 사용하고 수신부로는 PIN-Photodiode를 사용하였다. 실험을 위한 온도변환장치는 GIS와 같은 모양으로 재철은 알루미늄으로서 제작하였다. 광의 전송로는 파이버 내에서 편광상태를 유지할 수 있는 30[m]의 싱글모드 언재킷(unjacked) 파이버를 사용하였다. 전류의 측정은 400[A]에서 1300[A] 까지의 범위에서 측정하였으며 온도는 -40[$^{\circ}$]에서 50[$^{\circ}$]까지 10[$^{\circ}$]씩 증가시키면서 측정하였다. 이 때 출력선호는 인가전류의 중가에 따라 비례하여 증가하였으며 주변온도가 높을수록 비례하여 증가하였다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.04b
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• pp.85-88
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• 2002

We have carried out two-beam interference experiments to form holographic gratings on chalcogenide $Ag/As_{40}Se_{15}S_{35}Ge_{10}$ multi-layer. In this study, holographic gratings have been formed using He-Ne laser(632.8nm) under different polarization combinations(intensity polarization holography, phase polarization holography). The diffraction efficiency was obtained by +1st order intensity and formed grating structure was investigated using atomic force microscopy.

• Korean Journal of Optics and Photonics
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• v.5 no.3
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• pp.404-410
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• 1994

The contrast and the brightness of a liquid crystal display panel are expressed in terms of the characteristic parameters of the rotational transformation on the Poincare sphere of the liquid crystal (LC) cell, which is the geometric representation of the electro-optic polarization transmission characteristics of the cell. From these, we show that the contrast and the brightness of the displayed images can be maximized when the rotation angle becomes $180^{\circ}$ for the rotational transformation corresponding to the change of the state of the LC cell from non-select to select state. state.

• Proceedings of the KIEE Conference
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• 2002.07c
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• pp.1837-1839
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• 2002

본 논문은 패러데이 효과(Faraday Effect)에 의한 초고압 전력설비에서의 광CT 특성에 대한 기초 연구를 기술하였다. 광원은 LD(Laser Diode : 830[nm])를 사용하고, 수신부는 PIN-Photodiode론 사용하였다. 광의 전송로는 파이버 내에서 편광상태론 유지할 수 있는 싱글모드 광파이버를 사용하였고, 광파이버의 양끝은 편광자와 검광자를 두어 빛의 광학적인 편파면을 이용한 전류측정이 가능함을 확인할 수 있었다. 측정 결과에서는 기존 문헌상의 결과와 동일한 형태의 출력을 얻을 수 있었고 나아가서는 초고압전력설비인 가스절연개폐장치 (GIS: Gas Insulated Switchgear)에 대한 적용도 가능하게 했다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.299-302
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• 2000

In this study, we have made the large holographic surface relief gratings on amorphous chalcogenide $As_{40}$$Ge_{10}$$Se_{15}$$S_{35}$ films by two beam interference using a He-Ne laser(632.8nm) light. The film thickness was about 0.6$\mu\textrm{m}$, we could magnify beam size by using beam expander. We made use $90^{\circ}$ holder which was made of reflection mirror and sample. Formed the surface relief structures were investigated using optical microscope. The diffraction efficiency was obtained by measuring +lst order intensity. In addition we investigated grating formation and diffraction efficiency as a function of polarization states which is linear or circular polarization. The results indicate that the grating was formed by linear polarized beam is better clear than that by circular polarized beam.